First, there were the Twitter picture services. Soon, there were a lot of those. Then, there were the Twitter video services. And now, there are getting to be a lot of those. So how do you choose which one to use? Most people base it on two things: First, third-party Twitter client support. And second, features. Today, Vidly is launching one such feature. Vidly is claiming to be the first HD video service for Twitter. HD video on the web has always been sort of a hazy thing due to varying expectations of resolutions and bitrates, but it seems safe to say that Vidly's video is the highest quality out there among its competitors. Several of them offer video quality that can be grainy or choppy, but these new Vidly videos are smooth and clear.