I like the idea that you follow users, rather than tags on Hubski. However, this does not really come across in this website's design. I know this is a pretty new site, and a lot of the details have yet to be worked out, but a few things could be done to emphasise Hubski's "user-centrism".

First is by switching around a little bit of the terminology. There's a nice big "submit a post" button. But that feels very "reddit". You could change the text to something more along the lines of "share something", making it a little less like posting in a forum, but without discouraging people.

I would also make user profiles a little more "full fat". When you click on a username, in the popup window, the actual username is shifted off to the right of the page. It's very easy to blank out when looking at a profile. It causes a sort of disconnect between the content and the person, and doesn't encourage me to follow anyone.

However, I would NOT change the look of tag profiles. The fact that they aren't particularly inspiring helps this user-centrism concept.

Anyway, I'm rambling a bit, and I can't think of anything else right now, so I'll stop.

EDIT: Now I've posted my first proper item, another suggestion I would make is to put a user's newest post at the top, and have it move around the page based on time and "hotness". It's a bit ego-stroking, which is exactly why I suggest it.