That is so untrue! I made a full-time living in 2008 from PayPerPost. Social Spark has now become the big thing for Izea, and if you have a good blog with traffic and PR you can make hundreds of dollars per post.
Personally I have not made/attempted to make money from these site. But i know quite a few who made/still make upto 300$ even more. But what holding me back is almost all those sites page rank are stuck in the same state since they started the service n some last whatever PR they had. But if one have a personal site with PR 2 or more and with ~5000visits one can make 100$+.
Yes, you can make money. If you are a newbie with a new blog or website, then you can only hope to make a few cents. On the other hand, if you are an experienced person with a high traffic blog or website, you can make lot of money. Go for it if you have the requirements, or wait till your site makes some good traffic.