Backlink is a link of your site which is given to other sites for example other blogging sites like myspace , ning, Xanga ................. Backlink directly connects the site in which you are writting blog to your website which you are promoting in net ..........So that the visitor who visit your blog can simultaneously visit your site also to get a proper idea whats your website is about ...................
Do you only get the PR value of the page your backlink is on? What if someone puts your link on their PR 5 site but the linking page is only PR2? What kind of value do you get from that link?
Backlinks are incoming links to a site. In order for a site to get good rankings in search engines they need many backlinks.