Great post. I am a big time believer in the value of aggregating, filtering, sharing, curating. I think this provides significant value to yourself and your audience. It can really put you at the epicenter of the conversation in a particular space. For me personally, in the area of eLearning, my aggregation site: www.eLearningLearning.com and my blog (which is a lot of sharing as well), have made me extremely visible among a large audience. At the same time, I learn a tremendous amount and get in very interesting conversations. All of this is levels of sharing, but it's roughly the same thing.

I agree with you about the learning value of blogging, but I disagree a bit with your sentiments around business value. As a blogger, my audience is far larger than what I get from the time and money of speaking at conferences. I always tell people who hear me present is that they can get much more by subscribing to my blog. It's far deeper content. What's been missing (and is finally starting to appear via things like www.socialmediainformer.com) are ways to harness the collective value found in blogs into a very deep, rich publication like thing. There's no traditional publication that can keep up with these kinds of solutions. And if they do it the right way, it provides value back to the individual content authors. Value from blogging is still there.

Certainly subscription models are great. But they can be really tough to make happen. That Penny Gap exists in all kinds of places. I think that we got the conversion from free to paid just about right for eHarmony, but a lot of businesses can't dangle matches to get people across the threshold. My bigger concern is around Oauth and payment solutions. You may be right that in the long run we'll see dominance by a few specific single sign-on providers, but I'm pretty sure that right now a lot (most) startups shouldn't be relying on them. I recently wrote about this in my post: When to Use Facebook Connect – Twitter Oauth – Google Friend Connect for Authentication? http://socalcto.blogspot.com/2010/01/when-to-use-facebook-connect-twitter.html Love to hear your thoughts on this as I'm not sure these issues go away. And FB Connect's retention policies make it problematic to use.