Nambu Network closed the doors on its tr.im URL shortening service on Sunday, and claimed Twitter is partly to blame. The company made the decision to shut down the popular service after failing to find a buyer at any price.

"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 annointed bit.ly the market winner. There is simply no point for us to continue operating tr.im, and pay for its upkeep," the company said on the tr.im Web site

bit.ly is a competing URL shortening service that has become very popular with Twitter users.

URL shortening services initially became popular as an easy way to compress long and complex Web addresses into short links that are easy to copy. Twitter's 140 character per post limit, however, made the services even more popular since they helped conserve space in tweets.

According to Nambu Network, tr.im generated URLs will continue to properly redirect "until at least December 31,2009," but statistics shouldn't be relied on or even considered available at this point. The service has already stopped generating new shortened URLs, too.

The tr.im APIs are still functional, so developers can gracefully transition their apps to other URL shortening services.

As for Twitter's involvement, the company said "This shutdown was also not born out of any bitterness towards Twitter. While we are disappointed that users cannot choose their URL shortener, that is Twitter’s decision to make. We are simply accepting the business reality of the situation, and moving on."