The primary purpose of an icon is to visually represent data to a user. Typically, this data will have a meaning such as “this needs attention” or “click here when you want to save”. Since the icon is supposed to represent a single thing, it’s rare to see something like this in a shipping product.
I can’t recall the last time I saw the same icon appear twice on the screen, with different actions attached to it. Sure, one action is for the tweet and one is for the webpage URL – I get that. But that is a really subtle distinction that most users won’t be savvy to. Think of the joy of trying to explain that to one of your non-technical friends.
I can only assume this will be different in the next release.