If you want no hassle, affiliate sites are the way to go as you only generate the sales lead and they do all the rest. Once you find something that works, you just replicate. CJ.com is a good place to start.

I'm not sure what you mean by "blogging business" though, you mind elaborating?

Social sites where the users generate all the content are good as well, look into scripts like Pligg which are easy to install and customize to suite your niche.