Twitter never stops changing, it seems.
And when they acquire a company and/or its assets or employees, you can often predict that whatever that company does will be involved in upcoming changes to Twitter.
Early changes were to improve things for users, but more recent changes have been more about business, branding and advertising enhancements. (For example, recently Twitter announced that it would be controlling ads that run through Twitter more than ever before by changes to its API use guidelines.)
Here are all the companies Twitter has ever acquired, in one graphic, from a report by JEGI (click to enlarge):
Twitter’s first purchase, Summize, was a Tweet search engine, leading to Twitter’s own search engine.
Twitter’s two purchases this week were Cabana for mobile apps, and Vine for video sharing.