Google pretty much created link popularity. Before Google, no one cared about inbound links except for traffic purposes. But the other search engines have caught on and now all of them include link analysis in some form in their web page ranking algorithm. I find it interesting to compare Google data with Yahoo! data for a number of reasons.
Any time I check my link popularity, the first thing I notice is that I have a few links counted at Google and a lot of links counted at Yahoo! When I go to look at the links, I see that Google shows me one link from each domain and usually not much more. Yahoo! however shows me a lot of links from the same domain. Yahoo! also shows me internal links. Google doesn’t.
But I’m pretty sure that Google uses links to rank my websites in the SERPs. Yahoo! does too, but links aren’t as important at Yahoo! There are other factors more important there. What this illustrates to me is that you cannot rely on any one strategy for ranking at the search engines. You need to branch out and make your web building strategy more diverse – that includes links and it also includes other things as part of your long term search engine optimization and link building effort. The more diverse you are in marketing your website, the more likely you are to achieve high rankings where you want them.