Ozmozr alpha launched three days ago. Ozmozr is the work of The Center for Open Sustainable Learning (COSL) at the Utah State University and funded by the Andrew W. Mellon Foundation. It's billed as a "microformat-aware aggregator / resource sharing / social site." I see it as a del.icio.us for RSS instead of bookmarks; the two bundles of services are largely isomorphic. Since you are of course well familiar with the bookmarking service, I will just highlight the differences here.

One difference -- aside from subscribing RSS feeds vs adding urls -- is the greater emphasis on social networking by ozmozr. Del.icio.us' "my network" has elements of social networking but it doesn't seem to be emphasized, either by the service or users. (However, the "my network, subscriptions, and the explicit link sharing features of del.icio.us are indeed available and very powerful social discovery and filtering tools.) Ozmozr allows your profile to add friends, just like you can on MySpace. (How??) Also like on MySpace, you can join open admission groups focused on particular topics. Each item in your subscribed feeds can be shared with a friend or a group. Once shared with a group, they show up in a list to be voted up or down digg-style. Unalog project at Yale has groups and group links too. (In del.icio.us, all your links are available in the "my network" view.)

Another point of distinction is multiply-like meta-identity. Ozmozr can aggregrate accounts from 43 Places, 43 Things, All Consuming, Clipmarks, del.icio.us, Flickr, Last.fm, LiveJournal, Simpy, Wordpress, Xanga; an OPML file or a General RSS feed. Content from your own blogs are clearly distinguished Technorati-style (but without a similar authentication mechanism).

Where the similarity between Ozmozr and Del.icio.us breaks down is user motivation. I believe the key drive to use del.icio.us is the need to archive and access bookmarks centrally and have the power to find easily the links again later. Anybody who surfs much and has lost links quickly appreciates the proposition of trustworthy centralization. So the sharing and filtering are emergent collateral or incidental benefits that users may enjoy on the margin, but they are not the key motivators.

Ozmozr doesn't have the same one burning need. There's a number of ideas thrown out there -- microformat-aware aggregator / resource sharing / social site -- but what will get people to come? I think community. Twitter faces the same sort of Swiss Army-like flexibility and label defiance and what makes Twitter work is the draw of largely like-minded people who come to play with each other (and strong execution). Ozmozr's initial user base will probably be like Unalog's, academics who come together to share their web findings. Whether they, or Twitter, can hit the green fields of the mass market is another question.