to Twitter: So Long, and Thanks for All the Links is healthy and growing, says John Borthwick of Betaworks, which created and then spun off the URL shortener, even despite the fact that it’s no longer the default shortener used by Twitter. The messaging service broke off its formerly close relationship with in December, and CEO Evan Williams told developers at the Chirp conference in San Francisco this week that it will be developing its own URL shortener. As Twitter has been moving in on features and services developed by outside companies — either by developing its own or by buying them, as it did with iPhone app (s aapl) Tweetie — concern has been growing about the fate of so-called “hole fillers” in the Twitter ecosystem, and’s name has routinely been mentioned as one of the doomed.
Borthwick, however, who co-founded Betaworks and has invested in and/or founded Twitter tools such as Summize (which was acquired by Twitter) and Tweetdeck, says in a blog post that “is growing and continues to scale” despite the fact that Twitter “pretty much stopped using to shorten URLs on in December.” He says that now represents less than 1 percent of links that are shortened, compared with between 3 and 8 percent before the “transition” was made in December. Borthwick says that the relationship with Twitter worked well “during a period of hyper growth” but that both sides have effectively moved on. His blog post has the feel of someone writing a note to an ex-girlfriend after they have decided to break up and see other people:

We thank Twitter, everyone there, for the kick start it gave And we certainly hope we helped Twitter during a difficult scaling period.

Some have suggested that has been “screwed” by Twitter, but Borthwick describes this as “noise.” If the traffic numbers provided are accurate (and there’s no reason to believe they aren’t), it seems that has been able to leverage its close relationship with Twitter, and has sufficient scale and reach now that it’s no longer dependent on the social network for its business. Borthwick also says that the company’s Pro service, which recently launched a $995-a-month enterprise version, is growing rapidly.
Borthwick, who holds shares in Twitter as a result of the company’s acquisition of Summize, also talks about the somewhat tense relationship between Twitter and its ecosystem, saying:

Talk about holes and filling holes in platforms is misleading at best… Innovation — building great companies — is about finding, filling and even creating holes. But entrepreneurs shouldn’t — and most don’t — focus on filling holes in other people’s platforms — they should think about how to build great things — things that in 2010 may be bootstrapped on platforms but great products, products that people love, products that move people to organize their world differently, or to see the world differently.

When Twitter and created the relationship in early 2009, Borthwick writes that “knew this would be a short-term agreement — it was done to help Twitter scale and without a doubt it helped scale.” However, the Betaworks partner says that when Twitter decided to stop using “the change was barely noticeable.” Twitter’s web site now accounts for less than half a percent of the links that are created or clicked on in a day, he says, and there are “other social platforms that are now larger than,” although he doesn’t name them (likely Facebook is a major contributor).
Borthwick says that last month there were 3.4 billion clicks on links, compared with 2.7 billion in February and 2.5 billion in January — and notes that on Wednesday the company passed a new milestone, that of 150 million links clicked in a single day. The company has also had 7,000 companies sign up for its Pro service, effectively a white-label product that allows web sites and other services to create their own URL shorteners. Publications that use the service include the New York Times (s nyt), the Huffington Post, Foursquare, Pepsi (s pep) and NPR.

Related content from GigaOM Pro (sub req’d): As Twitter Develops, Developers Quiver in Fear
Post and thumbnail photos courtesy of Flickr user Nathan Gibbs