The offers generally fall into 'annoying but OK no big deal' and 'Uhh you want WHAT?!'
The 'Annoying' catagory invovles watching sponser commercials on youtube, or installing facebook apps. As I said annoying but fine, can live with it (and the apps can be uninstalled once points are gained.) These offers are low-reward/low-time intensive type things.
The other catagory involves surveys, filling out offer forms, and so on. Generally each of these has in common a part at the end asking for your home address.
I could understand wanting a zip code for ballpark location things since if they get a detailed enough map of where people interested in Brand X live they can shift resources accordingly. However I don't feel like feeling out stuff that will likely involve junk mail sent to me till the end of time. There are useful things like netflix signup (which I would do if I had the resources.) However mostly it's credit card offers and the like.
There is a third category that I absolutely loathe. Toolbars and other software installs. While the product might be solid (they do offer vlc) I'm very leery of advert tooled installer bundles. Why? Gee I dunno. Malware? Getting bombarded by ads constantly.
Thankfully there's an in game alternative. Involved watching little in-game adverts. Again low risk low reward. Generally gives you 'normal' credits you'd get from blowing things up. However once in awhile you get the 'has to pay to get' currency. Not much at a pop mind, but since it's just being handed out... *shrug*.
If it werne't for the potential sleeze factor of most ocf the surveys/offers I'd call this a viable alternitive. As is I say user be wary and make sure you read the fine print.