[therealdrag0]

Also Search (the article did says these wouldn’t fit to be fair but the discussion seems to be ignoring how much wouldn’t fit and why). Search is pretty expensive especially since to have it responsive you need the indexes to fit in memory—at least the Lucene variety, which at least in old YouTube videos Twitter used.

[marcusae313]

Twitter still uses Lucene. They built a custom codec for it, but doesn't change the cost too much.