BC SOCIAL MEDIA
Saved by @CodyyyGardner

It makes me smile every time I notice IGListKit at work in Instagram. We put a lot of work into making and improving it. Proud to see it holding up 4 years later.

🧵 with some memories on how it was built:

 At Instagram, product work slowed around the holidays, so we used the time to pay down tech debt. In winter 2014 I reviewed a +12k line refactor from UITableView to UICollectionView.

We recently dropped iOS 5 so we could use the new 6+ APIs without backwards compatibility.
That review taught me a lot about UICV: data sources should mutate in one place else risk out-of-sync exceptions, the first view layout may reloadData, sticky headers make good perf hard, and many more UICV tidbits
We used reloadData for everything and it worked, for the most part.

Except two things bugged the hell out of me:

1. No animated changes (duh)
2. Images could flicker and the like animation could cancel
I dug into the latter and learned that if you reloadData, every cell on screen gets reused. So even if nothing in the UI changes, you still reuse (or init) cells, bind data, set images, etc. that’s a lot of work!
When you liked a post, we’d call reloadData. Since all cells are replaced: we had to track the liked row, reload, and THEN perform the like animation. 😓

If something triggered another reload after the animation started, the cell cancelled the animation (thus the UI bug)
The image flickering issue was simpler:

When an image cell is reused set the background to grey, async load the image (cache or network), set the image. The async time between reuse and fetch/set from cache is where the flicker came from.
(@ryanolsonk solved the image flicker with an insanely clever “weak image cache” design. It’s a great interview question 😉 )
This all got me thinking: what if we only updated cells when the data changes? This general idea was gaining traction (ahem, React): bind data to views, and diff the data on change to only rebind changed data+views.

Enter UICV performBatchUpdates
Using the principle of only updating the data source in one place, I could diff the from/to data and use UICVs APIs to insert/delete/reload/move. Anything unchanged wouldn’t get touched!

So how the hell do I write a diffing algorithm? I literally had never done this.
I researched several algos: rsync, Myers, react...

I settled on Paul Heckel’s https://t.co/jpxuHNlpXg

Why?

1. It’s output matched UICV’s APIs: inserts, deletes, updates, and moves
2. There were example implementations I could actually understand
A pivotal decision was how we define identity and equality. I wanted to piggy-back off NSObject’s -hash and -isEqual: methods to spare our engineers having to write/understand diffing concepts.
@ryanolsonk convinced me I was wrong bc writing proper -hash is complex https://t.co/4PgDCykAna

Foundation hashes can collide
https://t.co/h9eVHO342U

Or are too basic for diffing
https://t.co/Pp0eVFRS5e https://t.co/ZNPJnXlXa4
We settled on a hybrid API: a protocol with custom identifier and -isEqual: We later scrapped the NSObject tricks as they were easy to abuse & forget, resulting in crashes.
Fun fact: the library was originally called “IGStoryKit” but my director hated that so we renamed it. Glad we did, guess what launched 6 months later? 🤪
Over the next several months, @jesse_squires and I refactored probably 20k lines so that we could run our new infra alongside the old one. This let us safely A/B test performance before rolling out.
We started with single-item feeds but quickly moved to support the main feed. Main feed was scary (we were starting to run ads 😬) but if we could replace feed, then the rest of the app would fall in line.
@ocrickard and I spent a couple months investigating crashes and tuning performance. I learned a lot about ObjC++ during this time (unordered_map was waaaay faster than NSDictionary for our diffing).
We ended up filing 4 UICV radars from all this investigation! Some have been closed

https://t.co/BACvyI2l08+
When everything was fixed, we launched. I spent a year advocating the eng org help refactor and deprecate the old infra. It came down to the profile view. I rolled up my sleeves and did it myself. It was TOUGH

With profile done, I submitted a -12k change to remove the old infra.
From the start we wanted to open source the library. It ended up being a lot of paper work and internal politics, but we did it. Forever grateful to @jesse_squires for setting the project up for success and @mikeyk for having our back.
We started writing the library in late 2015, launched feed summer of 2016, and deleted the old infra in early 2017.

Throughout this the eng team 10x’d and users 4x’d, we launched tons of products (Stories!), IG opened a NY office, UICV got diffable data sources, and more.
After we launched 4y ago I calc’d our diffing algorithm executes over 40,000 times a second. I can’t imagine what that is now!
Building IGListKit was a career’s-worth of learning packed into a couple years.

I’m proud that it’s still powering Instagram today, but I’m looking forward to learning about what replaces it.

More from Social media

Em\U0001f383jipedia \U0001f4d9
Em🎃jipedia 📙...
@Emojipedia
✨📱 iOS 12.1 📱✨
🗓 Release date: October 30, 2018
📝 New Emojis: 158
https://t.co/bx8XjhiCiB


New in iOS 12.1: 🥰 Smiling Face With 3 Hearts https://t.co/6eajdvueip


New in iOS 12.1: 🥵 Hot Face https://t.co/jhTv1elltB


New in iOS 12.1: 🥶 Cold Face https://t.co/EIjyl6yZrF


New in iOS 12.1: 🥳 Partying Face https://t.co/p8FDNEQ3LJ
SOCIAL MEDIA
David Harsanyi
David Harsanyi
@davidharsanyi
Don't know if anyone at CNN is covering debunking of the Cambridge Analytica whistleblower panic. This is what it looked like back in 2018.

https://t.co/zHneHwZbQE


https://t.co/VXCyV6rhfr


https://t.co/5JHO9FopEd


https://t.co/bcvkeqs8To
SOCIAL MEDIA
Advertisement
mark pincus
mark pincus
@markpinc
Tomorrow, Zynga shuts down FarmVille on Facebook after 11 years. I wanted to share the story of how we created it and why it has played such an important role in the evolution of gaming. 1/x

The real innovation of FarmVille was in making games accessible to busy adults, giving them a place to invest and express themselves and be seen by people in their lives as creative. People thought of FarmVille as a sort of Etch-a-Sketch. 2/x

It was the first game at scale that leveraged big data, and almost everything inside the game was tested and optimized. FarmVille became a training ground for a generation of entrepreneurs and product managers. 3/x

In 2008, Happy Farm reached 20+ million daily active users, setting off a wave of competition from game developers, and numerous farming games began to hit the market. 4/x.

On February 6, 2009, FarmTown reached 1 million DAU on Facebook. Farm Town combined the moving maps from MyFarm with avatars in Zynga’s YoVille. I wrote the date on the wall, and said we need to count the days until we are in the market with our own game. 5/x
SOCIAL MEDIA
David Kadavy
David Kadavy
@kadavy
An annoying feature in an "influencer" career is that it seems like you'll be much better off if you're "nice" to everyone.

You can always collaborate or "swap." You don't like their work, or maybe even them as a person, but gosh can you pass up this opportunity?

This might be an illusion. You're probably better off ignoring everyone and focusing on your own work.

Then again, it might not be an illusion. It's something I've noticed with successful Hollywood people. They're so damn nice. Either they are extremely agreeable people, or they have to fake it.

However, it's a much more people-oriented business than publishing.
SOCIAL MEDIA
KP
KP
@thisiskp_
10 ridiculously simple tips I wish I knew about building an audience when I first started:

I mostly winged it 🤫

Let me share my lessons so you don't have to:

(a thread 🧵)

1/ Switch from being a consumer to a creator

If your default is opening social media and binging on updates from others, there's a problem. The world needs to know what YOU can offer, and I believe everyone can add value. So first, switch to intentionally becoming a creator.

2/ Start very small and build "Atomic habits"

Most beginner creators people aim too far high and crash. It never works for me. Instead choose tiny habits like 2 tweets a day in the morning. Or 1 video for Youtube. Or 1 short essay each day on Substack. Optimize for consistency.

3/ Pick one social platform to create and stick with it

What comes naturally to you? Writing your thoughts, choose Twitter. Editing interesting footage and layering a voice-over? Choose Youtube. Short essays? Choose Substack. Pick one and stick with it for at last 1 month.

4/ Find your niche

Don't focus on big bold segments with hundreds of active prolific creators already fishing. Find specific audiences and move towards them.

I was a no-code maker in 2018 so that niche came naturally. Later, I expanded to the community niche. Now #buildinpublic
SOCIAL MEDIA , CONTENT

You May Also Like

XVIII Airborne Corps\U0001f409
XVIII Airborne Corps🐉...
@18airbornecorps
1 of 16: WE ARE ALL JEWS HERE: THE STORY OF RODDIE EDMONDS

One of the most moving and relevant stories of the Battle of the Bulge, or any American Soldier in any war, is that of Master Sergeant Roddie Edmonds, a Knoxville, Tennessee native, who served with the 106th Infantry.


2 of 16:

Roddie was captured early on in the Battle of the Bulge, on December 19th, when Panzer forces plowed through his unit.

He, along with almost his entire regiment, was forced to surrender.


3 of 16:

The men were transported to the Stalag IX-A POW camp in Ziegenhain, Germany.

Roddie was the senior enlisted American Soldier at the site. As such, he was the conduit between all American Soldiers and their German captors.


4 of 16:

In late January, the camp’s commandant, Major Siegmann [pictured here], ordered Roddie, a Christian, to identify all Jewish Soldiers and order them to stand in formation by themselves the next day.

[Jewish Soldiers were a minority within American units]


5 of 16:

Throughout WWII, captured Jewish Soldiers were often tortured and then killed by their German captors.

In fact, Jewish Soldiers had been told to bury their dog tags before capture. The dog tag identified Jews with the letter “H” for Hebrew.
SOCIETY
Simon DeDeo
Simon DeDeo
@SimonDeDeo
Donna Strickland, one of this year's Nobel Laureates, was not considered "notable enough" for Wikipedia as late as this May—reported by a number of sites, including the Independent. I dug into this a little. Here's the data—


This is the first deletion, back in 2014. A bit hard to read between the lines, but the basic story that an admin had Stickland's page "speedy deleted"—i.e., deleted without debate. The method was something called Copyright Jujitsu.

In particular, the admin had the page deleted not because of notability, but because it included a photograph of Strickland that had ambiguous copyright status. This is a method that people developed to get rid of content they didn't want, but also didn't want to debate.

"Copyright Jujitsu" because it is usually used against spam from companies; a PR officer uploads promotional material to Wikipedia. Instead of debating whether it's neutral, the admin can say "we'd love to have it, but the material appears to violate your company's copyright".

Usually the PR office and the IP office are separate in a company, and the idea of releasing promotional material under public domain is such a legal nightmare that the PR person goes away.
ALL
Advertisement
:Billy-Don :I-AM
:Billy-Don :I-AM
@ValiantThor12
1) 💜 THE EVENT 2020 - THE 1221 MULTIDIMENSIONAL STARGATE 💜
PLEIADIAN LIGHT FORCES TRANSMISSIONS - 12182020
CHANNELED BY MICHAEL LOVE
A SPECIAL MESSAGE TO THE STARSEEDS OF NEW EARTH, FOR IMMEDIATE PLANETARY BROADCAST…
PRELUDE:
THE FOLLOWING INFORMATION IS DERIVED FROM DIRECT,

2) DECODED ETHERIC TRANSMISSIONS FROM BENEVOLENT LIGHT FORCES DOCKED IN EARTH’S SOLAR SYSTEM AND SOME OF THE DATA COMES DIRECTLY FROM CERTAIN INSIDE EARTH ALLIANCE MEMBERS KNOWN AS THE WHITE HATS, AND THE GREAT WHITE BROTHERHOOD STRATEGICALLY PLACED IN KEY POSITIONS OF POWER BY

3) THE GALACTICS ON THE SURFACE OF PLANET EARTH!
THE DATA HEREIN IS RECEIVED AND TRANSMITTED FROM THE 5D LEVEL! THIS MESSAGE IS INTENDED ONLY FOR THE STARSEEDS OF EARTH!
GREAT ONES,
WE HAVE SPOKEN OF THE EVENT 2020 THIS ENTIRE EARTH YEAR AS ALL PLEIADIAN AND EARTH ALLIANCE INTEL

4) SHOWS INDEED THAT A MAJOR COSMIC EVENT IS GOING TO OCCUR IN ONLY 3 EARTH DAYS FROM NOW!
ON DECEMBER 21, 2020, A MAGNIFICENT CELESTIAL STARGATE WILL OPEN IN THE HEAVENS WHICH MARKS THE DAWN OF THE NEW GOLDEN AGE OF AQUARIUS AND THE 1ST DAY OF THE SATYUGA OF CENTRAL SUNLIGHT!

5) IN THE MORNING HOURS OF THE WINTER SOLSTICE, THE LONG-AWAITED NEW ERA OF LIGHT WILL FINALLY DAWN AND THE NEW 5D EARTH WILL BE BORN!
THE COSMIC GATES WILL BE FULLY OPENED ON 12/21/20 ALLOWING POWERFUL STREAMS OF COSMIC LIGHT TO ENTER EARTH'S ATMOSPHERE, UPGRADING ALL SENTIENT
ECONOMY
Noah Smith
Noah Smith
@Noahpinion
1/Politics thread time.

To me, the most important aspect of the 2018 midterms wasn't even about partisan control, but about democracy and voting rights. That's the real battle.

2/The good news: It's now an issue that everyone's talking about, and that everyone cares about.

3/More good news: Florida's proposition to give felons voting rights won. But it didn't just win - it won with substantial support from Republican voters.

That suggests there is still SOME grassroots support for democracy that transcends

4/Yet more good news: Michigan made it easier to vote. Again, by plebiscite, showing broad support for voting rights as an

5/OK, now the bad news.

We seem to have accepted electoral dysfunction in Florida as a permanent thing. The 2000 election has never really
POLITICS
DTBhat
DTBhat
@dtbhat
The thread explains my momentum scanner and how to build it in #TradePoint software.
@Definedge
Conditions :
1)EMA 8 above EMA 34 and rising
2)Candle close above previous 5 candle high
3) RSI above 60
4) Volume above previous 5 candles
5) ADX above 30
1/n

Select Double Moving Average 8 and 34
2/n


Under Patterns select Close Above Prev Bars
3/n


Qualify the candle close
4/n


RSI above 60
5/n
SCREENERS , SCREENER , A SCANNER