Pondering PageRank and TinyURLs

A couple of weeks ago I posted a link on Twitter and noticed it was automatically converted into a tinyurl (http://tinyurl.com). The URL was not too long to fit into my 140 characters.

This got me thinking, I have never felt the need to use tinyurls, but are they actually doing damage?

How do tinyurls effect PageRank? Should hosts fear a duplicate content penalty? especially if tinyurl.com has a higher initial page rank than your own site?

Has anyone seen googles algorithm deal with these URLs in a good or bad way? Are all these great links in twitter going to waste? Surely not?

There is some debate about this topic here :


I would be interested in any views on this.