According to Technorati, the topics feature was seeded with popular blogs that were chosen by taking into account a combination of "Technorati Authority, frequency of posting, use of relevant tags, links to related subject matter and general topicality."
The topics page presents 10 stories in a continuous scroll, though it's unclear if they are the most recent from the pool of blogs or they are decided upon via some other mechanism. Reloading sometimes causes the scroll to back up to the beginning and the time stamp is oddly different on each topic (and as the screenshot below indicates, I'm not sure why today's new blog posts in the sports category were previews of games that happened over 24 hours ago).
Unfortunately, Technorati's scroll of news moves so fast it defies usefulness. In the space of a couple of minutes 30 or so stories might fly by -- hovering your mouse over a story stops the scroll, but that doesn't do much to alleviate the information overload. Further, once a post drops off the scroll (which doesn't take long) it appears to be gone for good.
Technorati's topics won't make me switch from Techmeme, which rather than just posting stories from top blogs, posts the stories that multiple top blogs are writing about (at least in theory). Techmeme acts as a filter for the most important news stories, instead of just a mouthpiece for the top blogs. For now, Technorati's topics holds little value for me, and I think it would be more of a distraction than a helpful source of information.
However, Dorion Carroll, the VP of Engineering at Technorati, wrote in a blog post that, "Today's release is just a first step. There is a lot more we have up our sleeves, so stay tuned for what's coming next and come back often." Hopefully further refinements to the topics system will make it a more worthwhile view of what's being talked about across the blogosophere.