I don't use it, but it looks like all people do there is link to web articles that they like on other sites. I've seen lots of my hubs there. They'll give a short excerpt and then a no-follow link. I don't know if they get paid for the ads, but I do know one thing...they outrank me using my own content!
I tried looking into it to see if they get paid, but all I saw was that they can get a free account, or they can pay for higher level accounts. Maybe the higher level paid accounts offer monetization options? I'm not sure.
I'm actually hearing some good things about Bubblews right now (but yeah, some people copy hubs and put them there too...not cool). But some hubbers are making more over there than on HP, so I was gonna check it out. Just haven't got the chance yet.