It's no secret that Twitter is now putting others' favorites into your timeline, but the actual trigger for those appearances has remained a mystery. Is it purely random? Keyword-based? As it turns out, it's more like a slot machine. The company's Dick Costolo has revealed that those favorites appear when you pull to refresh twice, and there aren't any new tweets to show. Twitter is simply trying to respond to your insatiable demand for updates, Costolo says. In other words, the social network would rather give you some recycled tweets than leave you hanging.
The approach makes sense, especially given the company's endless efforts to keep you active; it doesn't want you quitting because you've run out of things to read. It also explains why those who follow a lot of people (such as yours truly) tend not to see these unexpected faves. Still, the explanation isn't going to be very reassuring if you use favorites like bookmarks -- a very bored Twitter user may end up discovering your tastes in content, whether or not you're prepared to share them with the world.
@AstroKatie ...2x request for more content is a strong signal that person wants more content. So the goal is to respond to that well.- dick costolo (@dickc) August 31, 2014