I'm not sure exactly what you're envisioning, but I've been working (on and off) a side project that sounds very similar. The name I have is InfoStream (not Trademarked), and the domain is infostre.am (not currently in use). I will E-mail and tell you more about what I was envisioning in terms of my project, and we'll see how it matches up with your vision. If we have a match, maybe we can work on it together (or maybe I can contribute somehow). The problem I came up with was Monetization, specifically on the Twitter Platform. Twitter seems to be the best source of real time information, but when they introduced API 1.1 and the (IMO) extremely gray 1.5 rule (do not replicate the core twitter experience) I placed this project on the back burner. It just does not make sense to dedicate time to a project on a platform that will likely pull the plug [1]. In many ways, the vision I have (InfoStream) is replicating the core Twitter experience. I find Twitter's approach towards filtering data (lists) and presenting data to the user (single context feed) to be extremely weak, and ripe for innovation. Yet delivering this information is the core Twitter experience, and thus even though I think I can provide methods to deliver information better (more contextually accurate, more valuable), this is not what Twitter wants. So I end up where lots of other people have ended up; Could build something cool on Twitter, but it's just too unstable from a Developers perspective. If you can think of other Sources for real time data that are not as controlling, more trustworthy, and/or easier to Monetize, I'm open to trying a different approach. Unfortunately, I don't think Twitter is a good choice. And I am hoping that an IPO will change things (but I'm not sure).
[1] http://www.linkedin.com/today/post/article/20130417052642-32...