I was thinking recently about how link text has changed over the years, as the online landscape has changed. In the pre-Google era, and before SEO had widespread adoption, link text was often simply the URL itself. You'll still sometimes see this on personal sites and some education sites, where a link is written out as:
- http://www-csli.stanford.edu/~hinrich/information-retrieval-book.html - info on information retrieval from smarty pants
And that was a pretty common way to link out, for example on things like directory pages which used to be so common. (Hearken back to the good 'ol days of Geocities.)
That's changed as the web has evolved, and using descriptive link text is pretty much the de facto way to link out. It's better, it's cleaner and more informative (at least it can be). But then a funny thing happened, Google came along, and links became currency. And anchor text became gamed.
If we could compare the landscape of the web in 1996 to the landscape in 2009, and cross-examine the density of keywords in anchor text vs URLs in anchor text, I'd be interested in those findings.
With nofollow (a fiasco from the beginning, in my opinion), with paid links, with the extreme measures people now take to manipulate search engine rankings with link text, this could be an interesting topic to explore more.
All things considered, it really is all about the backlinks.
And now we have Twitter. How will the hundreds of thousands of links being posted on Twitter daily, with URLs as link text, impact SEO? We've come full circle, in a way, and also moved into new territory where shortening services are, or may be, new signals to the engines. A new landscape of transient, redirecting URLs without link text. A new landscape of influence.
For now and maybe for the future, it's still all about the links.