And the quality of the service they offer is greatly shaped by their design. Of course Twitter uses Bootstrap—it was made by/for Twitter. However, Bootstrap's

And the quality of the service they offer is greatly shaped by their design. Of course Twitter uses Bootstrap—it was made by/for Twitter. However, Bootstrap's defaults are based on Twitter's brand guidelines. That's part of the problem: with Bootstrap 1 and 2 basically every website made with Bootstrap looked a lot like Twitter. Bootstrap 3 alleviates that by encouraging customization and shipping with a flat appearance, but sites made with Bootstrap are still very similar to each other—developers don't customize it, and don't try to change some of Bootstrap's easily recognizable idiosyncrasies. It reminds me of 2004/2005 when every web app was more or less trying to copy the aesthetics of 37signals apps.