This generation web advertising

After writing last week a short review about the advertisement site 43ads.com I got some interesting comments about other nice Web 2.0 styled advertising ideas.
bla.st
This is a nice combination of free and paid advertising, in the beginning you will get a spot on the first page of common key words like “web-design”. Interesting at this site is, that your ad is live after submission and the possibility to get a direct information how much a bid will raise your ad on selected pages. The website is really clear and you get the chance to have a 270×165 pixel banner ad for free.
ispuare
I found this advertising site via other blogs about the popular “Web 2.0 advertising thing”. Placing a link is for free and after that I got the invitation to get also a free “square” in exchange for a link. Sure the websites idea is very “original”, but I’m not sure that this is the “coolest” way to surf the internet. Placing a square inclusive an extra text link is € 50 at the moment.
At the end I’m asking me, who will visit all the websites behind the ads? In these days there is a lot of traffic because of all the blog posts but what about the real visitors a website need to sell products?