I am wondering how google finds out about sites selling links. How will they differentiate one's own links and sold links?
they dont need to be sure, but they can detect possibility of "illogical linking" if there are many linked sites from different niches if there is possibility of that - they do not count this links (like nofollow), PR can penalised - but it will not have direct effect on serp: will be no bad effect on serp for site who sell link, but also will be no good serp effect for site who buy link no sepr changes for site that sell links (and not buy links) - because they cant be sure that you do that /IMHO
also there is link that you may submit link buying/selling sites to google in webmaster tools www.google.com/webmasters/tools/
I am sure they also have list of sites spidered that says buy link and increase page rank. I am sure they also check forums for sites that says this
-webmasters reporting links on each other -advertisements that say "sponser link" etc -visit major/important/popular websites that is selling links -DP members (or any other forum)that sell links on sites in their sig This is the huge majority of the cases of people being caught for selling links. All the fear mongrels and google claiming they can simply detect paid links have not proven a single case. If google could detect paid links from a algorithm already they would not need webmasters to rat on each other with all of the engineers and people working at google.
I am sure they do it 100% automaticly, But they use public information to get new algorythms, so its highly possible that sites wich they find can be penalised faster than others...
Yup, my guess as well. A key to detect "unnatural" (traded, bought) links would be the link location, e.g. footers, blog sidebars, etc., especially if there are several unrelated links or a huge number of links in one place of the html code. So, I'm pretty sure it's easy to get penalized even if you don't sell or buy links, big collateral damage. Looks like "in content" links are the safest way...
If you have tons of links to spammy sites, they'll know. But if they're quality and related sites, I don't think they'll know. It's beginning to sound like a bad neighborhood thing, but it's the links on your site taht matters.
is that actually any good, wouldn't it alarm google with red light and make check your site more and then booms bought links and PR 0 ????
All they need do is check their own Adwords. Guess they don't have a problem taking money from sites selling links though. http://www.google.com/search?hl=en&q=buy+pr8+links&btnG=Google+Search
I'd guess it would be a ratio between content and links. I don't think Google punishes legit websites for selling links as it is like selling ad space. What is wrong with it? But if your site looks like a FFA and have no content google will definitely penalise you, even if you were to give out these links for free! Why do a FFA when you can do a directory?
Its easy for Google to tell if a site has bought links. For example site A outranks site B, site B wants to get ahead of Site A, Site B buys some links for Site A, Site B then reports the paid links to Google. Hey presto Site A disappears into oblivion for buying links and Site B moves up to secure a higher position left vacant by Site A, Google pat themselves on the back for their brilliant and foolproof new system for improving the quality of their rankings and everybody's happy.
Every hosting company is assigned a range of IP addresses. So if you have different sites, host it with different hosting companies to avoid coming under google radar. As for google finding out about sites selling links, most of the time, this is done by your competitors reporting them.
Another way of goggle finding out who sells and buys links, is by checking their search logs (google), of those who search for buying links. They take note of the kewords used and the landing site and then manually check that site.