I know that for a high place in search engines, you have to have many related link from you domain.Now I'm asking how google determine if a link is related to your website ? He analize the content from that page or how ?
Things such as the incoming links to the page / site where your link is found, page title where your link is found, content on the page, other links on that page, where on the page the link appears, etc.
In the past if you had three sites A, B, and C and if A and C were linked to B then A and C showed up as related regardless of themes of A and C.
I think Shannon and I were talking about different things, now both sites of the related questions have been answered. She was referring to the related: operator in Google and I was referring to relevancy of links.
I have noticed something else about links relevancy for one of my sites, I don't know if it is a coincidence but here it goes. I have a site A that has a one way link from a site B (not mine) Site B has a lot of one way links from sites that are irrelevant from both sites A and site B but all of them are from the same niche. Now both sites A and B have a really small section about the niche of these sites ( probably less than 5% of their total content). Now that niche themed section of my site (site A) doesn't have any outside links pointing at it but ranks fairly well. So my conclusion is that a link from a site that has a lot of themed links from a certain niche but doesn't have much content about that niche can still be considered a relevant link by Google. I hope I didn't confuse everyone