I ran across this posting on Slashdot last night & thought that is was worth mentioning here:

Indus Khaitan writes "Thanks to twitter, SMS, and mobile web, a lot of people are using the url minimizers like tinyurl.com, urltea.com. However, now I see a lot of people using it on their regular webpages. This could be a big problem if billions of different links are unreachable at a given time. What if a service starts sending a pop-up ad along with the redirect. What if the masked target links to a page with an exploit instead of linking to the new photos of Jessica Alba. Are services like tinyurl, urltea etc. taking the WWW towards a single point of failure? Is it a huge step backward? Or I'm just crying wolf here?"

My thought on this is...what about the fact that twitter defaults to shorten all URLs using TinyURL whenever you tweet them & they're longer than 140 characters. Twitter is becoming really dependent on TinyURL for their service. What is TinyURL ceases to exist in 2 or 3 years....thats 2 or 3 years worth of history on every twitter user's page that is thus polluted w/ non-working URLs. If I were twitter, instead of becoming entirely dependent on TinyURL for shorting URLs w/ your service, I would purchase TinyURL or reverse engineer their service & run it in house to give insurance to your users that this wont be an issue.

That aside, this does present a question for the net in general...what if all of these shortened URLs suddenly stop working? What will this do to link dependent analysis such as Google's page rank? Anywho - just some things to ponder.

Update: Now this is funny.....not 5 minutes after I posted this, I noticed on Twitter that the TinyURL posting to this blog entry was broken because...wait for it...TinyURL was down. Har har! On that note, Read/WriteWeb has this to say on the subject:

Written by Marshall Kirkpatrick
The link shortening and redirection service TinyURL went down apparently for hours last night, rendering countless links broken across the web. Complaints have been particularly loud on Twitter, where long links are automatically turned to TinyURLs and complaining is easy to do, but the service is widely used in emails and web pages as well. The site claims to service 1.6 billion hits each month.
There are many free public alternatives to TinyURL, some with better ancillary features (see elfurl.com for just one example). The name TinyURL is very literal and memorable though. I use SNURL more often, myself.
It's not good when so much of the web runs through a single service. For some, politics could be a consideration as well as technical considerations. The man behind TinyURL, Keven Gilbertson, uses his hugely popular website to promote US presidential candidate Ron Paul, which I personally find somewhat distasteful, and encourages people to use TinyURL to obscure affiliate links on their webpages - which strikes me as extremely distasteful. Presumably a Paul supporter would want our redirects to run wild and free too, unbeholden to a centralized service provider capable of holding us under its thumb (I joke, but really.)
URL shorteners are important because they make long links much easier to communicate. The print world could learn a thing or two from these services; InfoWorld magazine, for example, used to to publish very short redirects through infoworld.com for all links it discussed. That's great for efficiency and brand recognition and makes me wonder whether all of us ought to have our own private TinyURL service.
If there was some sort of distributed standard or tool that could be good as well. The Online Computer Library Center (OCLC) has run Purl.org (Persistent Uniform Resource Locator) since the 1990's but user experience is something only a librarian would put up with. A public institution solving this problem gracefully might be as realistic it would have been for the Library of Congress to have acquired Del.icio.us (my fantasy) instead of Yahoo!
The moral of the story, though, is that it isn't supposed to work this way. There ought not be one single point of failure that can so easily break such a big part of the web.

The bit above, that I bolded, concerning TinyURL & Ron Paul angers me a great deal. I am participating in Wonkette's "War On Paultards" in which the liberal blog, Wonkette, & the conservative blog, RedState, have banded together to wage war on the idiot supporters of Ron Paul that are polluting the net with their ilk.

Update 2:

David Winer has commented here with:

Creating a maintainable and thriving web

Steve Rubel writes about the danger of routing all our URLs through TinyUrl. I love what URL-shorteners do, it's especially important in Twitter when you're limited to 140 characters to express an idea. If you have to include a link, that could use up a lot of the space you have. The problem is if everyone uses TinyUrl, as Twitter does, what happens when TinyUrl goes down or is sold to someone we don't like, or disappears forever? I admit I don't know the owners of TinyUrl and what their motives are. Their service is reasonably long-lived, reliable and quick. Even so I've written my own URL-shortener and am running it on one of my servers, and I try to use it whenever possible. However, like all my sites, this one will likely disappear within a few days of my passing. I have to maintain my servers to keep them running. A better solution is surely needed. Rubel's epiphany just exposes the tiniest sliver of the huge problem below, creating a sustainable web. We're nowhere as far as that's concerned

Steve Rubel's post itself is worth looking at for the sake of its good analysis of the uptake in traffic that TinyURL has gotten due to Twitter.

Could a Billion TinyURLs Go 404?

TinyURL, a free and extremely popular five-year-old web service that shortens URLs and is a staple of tools like Twitter, has suffered some brief downtime lately. It's down as of this writing, as you can see from the screen shot below.
As a result, some are starting to imagine what might happen if such a single point of failure should go down for an extended period of time or, worse, shut down or be acquired. Twitter is far from the only company using the TinyURL API service.
The thought of an evaporating TinyURL - a wonderful tool that remind you is provided to us all for free - especially considering its rising popularity is all more than a little bit frightening, yet fascinating. Take a look at the chart below, which comes from Google Trends. It shows TinyURL clearly rising. No wonder it's having a hiccup!
Perhaps Google or someone else will buy TinyURL at some point. Still, that's not a good solution since all roads still lead to one. All of this points to a big weak spot in the web as more people and services rely on the terrific TinyURL service (and its alternatives).

Update 3: David Berlind at CNET says: Yesterday, Slashdot asked ‘What if TinyURL goes down?’ Today, it’s down (and it hurts).