I have recently started using Twitter a lot more. I tweet every so often but I also regularly follow some 
people that have smart things to say. What I have noticed though is the degree to which people are starting to share links to content on the web through Twitter. More precisely, I have noticed the degree to which there seems to be a shift away from blogging to share stuff and toward tweeting a tinyurl of it. Microblogging through Twitter or Tumblr, etc. seems tailor made for this form of “conversation” of callouts to cool and interesting things. Many of the people whose blogs I follow have definitely shifted their behavior to use Twitter more often and are posting more links there.
Blogs seem to be reserved now for more thoughtful analyses and longer expressions of ideas. To be sure, these posts still have links, but I would really like to see a study of whether their volume of links has declined over time.
Why is this an issue? Well mainly because the prime way people find stuff on the net, Google, is focused on determining contextual value and authority for certain topics based on the links connected to web pages. If the “linkerati” are increasingly doing their linking on microblogging platforms whose links are no-followed, where will this leave the value of the google index?
At least some of the small url services, like http://zi.ma, are providing link love value by providing 301 redirects in their urls so that when people just copy the small urls from Twitter and paste them in their blog, there will some value passed to the target page. But as the “net” disperses from traditional “pages” into other forms like tweets, where will this leave search? Where will it leave the link focused algorithm? I don’t have the answers yet, but it would be great to hear someone else asking or starting to answer the question…