Why can't you just produce and consume interaction streams?

So, I read with interest Matt McCallister's plaint last week about how long it is taking RSS to reach the mainstream. The weird thing is that by many measures, RSS is mainstream but just not widely recognized as such. After all, 31% of the online population use it, it's just that 90% of this group don't know they are doing it.

Given the gnarly technical nature of RSS, Matt wonders, rightly I think, what the sales pitch is to the average user. Why is it useful? Well, it's clear that the idea of being able to subscribe to the sites you want in your portal page is taking off. That's where the 31% comes from. But, it could be better. Instead of treating blogs and other small publishers as junior content producers for aggregation by the monetizing big boys, why not make it just as easy to subscribe to a small site's stream of interaction. I get the site-owner's data as well as the site's stream of comments and trackbacks. That's really where it's at for many small sites I deal with.

Sixapart and Blogger, two of the biggest blog providers could easily provide these streams. Their SPAM controls are adequate that the signal-to-noise ratio on interaction streams should be quite good. That way, as a consumer, I'm free to join community as I see fit without having to visit the site every day. Portal publishers should love it because it is yet more free content. Maybe their allied community sites won't though because it breaks their ownership of the community space.