Search Engines cannot manually go to each site and check their content. They let other humans do that work for them.
How to choose your link partners
Choose your link partners from the benefit of your visitors.A web site with good content that has a low PageRank you should link with that site if that web site is useful for your visitors.
How To Get Rank from link building
In the past a web page's ranking was determined, amongst other factors.To gain a better understanding of link popularity it is useful to know why it became so crucial for search engine rankings.
What is 3 Way Linking?
Search algorithms may consider it a two way link trading as an artificial means of boosting the popularity of both sites.Search engine might give lower link juice for both side and discount the value of these links.Link to site relevant to your blog.
Fair level of page range linking..
If you are focusing on PR, then it needed to comfirm the PR of the page that actually has the link. If the page has a PR0, It's not that "fair"to trade.However.,If the link is relevant to your site,and has valuable content.Forget about PR.
7 points to Building your up Your Link Campaign
I ignore all "Spam" reciprocal linking requests. Spotting Spam should be easy for you as the messages sound canned and non-personal.