It seems as the market for content-creation expands, there is room for infinitely more products simply by taking the mid-point of any two existing products. e.g. Twitter, the mid-point of blogging and IRC. Tumblr, the mid-point of blogging and Twitter. And now DailyBooth, the mid-point of Twitter and Flickr (?). There's also 12seconds.tv, the mid-point of Twitter and YouTube, but I think that's a really stupid idea (Robo.to is also in that space).
So logically, the next product should be the mid-point of Twitter and email... oh, Google Wave.
So logically, the next product should be the mid-point of Twitter and email... oh, Google Wave.