Over the weekend URL shortening service tr.im decided to call it a day. They posted the following statement:

"tr.im is now in the process of discontinuing service, effective immediately.

Statistics can no longer be considered reliable, or reliably available going forward.
However, all tr.im links will continue to redirect, and will do so until at least December 31, 2009.
Your tweets with tr.im URLs in them will not be affected.

We regret that it came to this, but all of our efforts to avoid it failed.
No business we approached wanted to purchase tr.im for even a minor amount.
There is no way for us to monetize URL shortening -- users won't pay for it -- and we just can't
justify further development since Twitter has all but anointed bit.ly the market winner.
There is simply no point for us to continue operating tr.im, and pay for its upkeep.
We apologize for the disruption and inconvenience this may cause you."

What tr.im say is true, there is almost no way to monetise URL shortening, and its easy to see why they’d be disgruntled at Twitter choosing a default service from the many popular ones out there.
Does anyone know the reasons why Twitter made this choice in the first place (aside from having to move away from tinyurl because, well, the URLs aren’t tiny!)?

It will be interesting to see what happens in this fledgling market place.
Is this the first of closures that will see a complete move away from dedicated shortening services to ones which are simply a bolt on of another, more monitisable site (such as su.pr). Or will one service (bit.ly?) become super-dominant and create a shortening monopoly (if so how would that work, the paths would eventually become too long, they would have to shift to another domain or recycle URLs...?).

Why did I use tr.im – two reasons, firstly the URLs really were short, at least one character shorter than bit.ly, and secondly the easy to use, easy to view stats that came with it.
What other URL shorteners are there out there that provide this sort of service? A while back Danny Sullivan did a study and survey into this, and has this morning promised an update to the chart... so we shall see!

UPDATE: mashable reports bit.ly have "offered to host [tr.im's] url mappings starting tomorrow", although whether this happens, or whether bit.ly simply buy tr.im for a nominal fee, remains to be seen (tr.im blog: "For the record, I will not sell the domain name to spammers or speculators for any price").