There are many blogs that gernerate revenue, usually they sell ad space, links, or via adsense.

I blog a lot and have several blogs. The advertisements that you are seeing are called affiliate marketing. The bloggers is an affiliate of the advertisers that you see.

To become an affiliate you should search for Commission Junction and LinkShare. These are two of the largest affiliate networks.

Also some other websites have affiliate programs, like eBay and Amazon.com that pay bloggers to post advertising on them. Google adsense is another method of getting ads on your blog.

To give you a specific answer to your question, yes many bloggers make money from advertisments. How much they make depends on many factors i.e. the amount of traffic they have, the details of the affiliate program that they are a part of, what they are being paid for (pay per click, pay per sell, pay per lead, etc).

You can read more about this in my blog Affilinfo.