Let's get this out of the way before I go any further. Poodz is a terrible name for a start-up, but I'm willing to give the founders a break since the more understandable Podz.com is parked, and the developers are French--so maybe there's something lost in translation. The default brown on brown color scheme, however, might be in poor taste.
The service is best described as a Twitter that adds photos, videos, and sound clips. This can be managed over the Web or on your mobile phone. Any combination of content can be sent via MMS, which includes whatever videos or photos you've captured on your mobile device. The entire operation is similar to Pownce, in throwing mixed-media sharing together into one big pool and seeing what happens.
While the site is entirely in French, once you've registered you can swap back and forth between French and English localizations; however, users of both languages are kept in the same pool, which can result to some trips to Google Translate or simply ignoring responses or messages you don't understand.
Poodz does a few things better than the competition. For one, it's got tags and a robust search engine. While the search engine is limited to users and channels (more on those later), the tags are really well implemented and let you dig through posts you've made quickly and easily. It's also very good about separating your post types, by placing little photo, video, text, and audio icons to the left of each of your posts. Each of these also constitutes a specific RSS feed, so if you felt like only subscribing to a friend's video feed, you could skip the other message types entirely. You can also take any audio or video recorded on the site and embed it elsewhere. Twitter-a-holics can even plug in their login and cross-post messages to the service every time they tweet.
The other key differentiator is the integrated social discussion network called channels. It's the equivalent of e-mail newsgroups, but it uses the same system as the content posting, letting members post whatever they want as long as it has to do with the channel theme. Each channel can have casual observers, or full on moderators who get to treat the channel content like posts on their own accounts--editing and deleting at their discretion. It's an interesting concept, and something that's been a requested feature from Twitter users for a long time now.
So is Poodz worth ditching Twitter, Pownce, et al to join? While more feature rich and customizable, the crux of these services is all about the community and where your friends are. It's an unfortunate truth that nearly all of these services face a similar battle for user attention that any other new social network has when launching in a world of giants like MySpace and Facebook. However, if Orkut's taught us anything, your service can be hot in a few specific parts of the world and do just fine.