I do a fair amount of Rails, so I'm really curious here. How could it be that they've so heavily patched 2.0 that they can't move on? Anyone from Twitter care to comment?<p>I've worked on many Rails apps, and have upgraded the apps from version to version. It's a pain when key elements of the API shift, but it's not <i>that</i> bad...even when the project has monkey-patched Rails a lot. And twitter certainly has the resources to afford to dedicate a few programmers to this task, so I'm just not sure I buy it.