Actually, much more. My company did a test project recently to test if a search engine that listed only non-affiliate-advertising pages was feasable. This is pretty simple to accomplish, by making the web crawler look for adsense/cj/amazon/searchfeed/etc. links in the HTML before allowing the URL to be added to the index.
What we found is that less than 5% of the pages we crawled would be allowed into the listings. We still may proceed with the project, but the test showed that nearly all of the most popular sites on the Internet were making money through affiliate advertising and could not be automatically deemed of lessor value just because of the presence of those ads. This may be obvious to most people, but we just wanted to prove/disprove it.
Interestingly, the majority of web sites that got added to our index were mom-and-pop business (commercial) type web pages, not blogs or hobby sites.