Question: Recently there has been a lot of hype about URL Shortening. I guess some URL Shortening services even offer tracking stats. But, doesn't adding one more level of look-up to the original URL affect page ranking in any way? Just curious to know.

Answer: 
It might, right now, but I wouldn't expect that to last for too long. SEO and PageRank are subjects where a lot of guesswork is passed off as wisdom.

If you're that obsessively worried about your PageRank, here's what you do. Take that energy, and put it into creating content that people want to link to. You'll get better results.

People buy stuff. Robots don't.
Well, I can tell you one thing that *won't* affect your PageRank - URL shorteners using DNS.

The vast majority of URL shorteners use clientside redirection - either via scripting/meta-refresh, or via frames. Those might affect your ranking as they change what Google sees - you never know. Examples are anything from [Dot.tk](http://dot.tk) to [PopNIC](http://www.popnic.com/), [Smartdots](http://smartdots.com), [JoyNIC](http://www.joynic.com/), [HomeNIC](http://www.homenic.com/), [EuropNIC](http://www.europnic.com), [Tipdots](http://www.tipdots.com), [DuoNIC](http://duonic.com), [UnoNIC](http://www.unonic.com/), [Cydots](http://www.cydots.com/), [FreeNIC](http://freenic.at), [Mediadots](http://mediadots.com), [Ulimit](http://ulimit.com), [kurzURL](http://kurzurl.de), [co.nr](http://co.nr) and [de.be](http://nic.de.be)/[de.vu](http://nic.de.vu)/[ch.vu](http://nic.ch.vu).

A few services are using proper DNS for forwarding, though. Those include [Afraid.org](http://afraid.org), [co.cc](http://www.co.cc/), [No-ip](http://no-ip.com) and [Da.ru](http://da.ru). This is fully transparent to visitors and spiders, so you can be sure it doesn't affect your rank.