Much has been written about the negative effects of url shorteners on the internet, and I agree that their net benefit may well be destructive, but I’m not getting into that. (And anyway, if zth.rs cost less than $500 per year, I’d be all over it.)
My issue with shorteners is their unnecessary use. Twitter for mac is my pet peeve culprit. It’s view of this tweet is simply the string ‘http://t.co/1vdl3Tx’. Even the web interface currently shortens the visible url to ‘kottke.org/11/04/your-tas…’. Even though the regular URL, ‘http://kottke.org/11/04/your-taste-is-why-your-own-work-disappoints-you’, falls well within the 140 limit!
But shouldn’t I be giving more context to random links I drop? Well not really, your service doesn’t let me define the link text to give context, and when if you’d left the damn thing alone it would have said enough in itself!
Webmasters spend a significant amount of time crafting good, understandable, URL schemas. So don’t shorten my damn links if you don’t have to.