As Edwin said they are identified by User-Agents like Googlebot etc. The PPC companies have to screen that out.
Thanks for the tip. Here is another one. I am using tracking software which adds some stuff at the end of the url. As far as I know that url is static. I have following questions: 1. Does crawlers, especially googlebot, concider ppc listing to be a backlinks? 2. Does the tracking code at the end of the url has any effect on those backlink results? Best Regards, Andrey
depends on the tracking code. if it uses "session ids" it is a definite no no for google. usually the ppc pages are low quality, low pagerank pages that will pass very little PR, if any. what you might want to consider is engineering a text ad link from a high pagerank site in your niche. that serves two purposes: 1) gets you on topic traffic 2) gets you on topic backlinks and pagerank that might be worth a portion of your campaign.
That makes a lot of sense. The biggest problem is, as you have mentioned, to find a good ppc with good PR. As for the whole tracking deal, I only use it for ppc se and banners.
Most websites aren't going to publically state they're "selling PageRank". However, you can easily click on a high PageRank site and see if the offer sponsorships or listings. Just make sure they don't use dynamic linking or anything that would make the link not count.