Refollow, an incredibly useful service that helps Twitter users easily curate their following, has suffered a major setback today at the hands of Twitter. The company posted the announcement on their website earlier this evening for users who login via the OAuth option. Refollow, which we wrote about in September, is part of Originate Labs‘ portfolio. Refollow’s CEO blogged about the issue today. More details are also streaming in via Refollow’s official Twitter page.

Refollow is obviously unhappy about this. In the message posted on their website, they remarked that , “Twitter decided to suspend Refollow…for enabling you to follow/unfollow too many people. Apparently that’s not what Twitter’s all about“. They also tweeted that “Twitter has suspended Refollow (via OAuth)…They could have at least returned an email!”

Refollow was a great product because it allowed users to build a large, quality following in just a few days. This has been helpful since Twitter made it a rule that users have 2,000 followers before they can follow over 2,000 accounts. Even when you cross this threshold, it is nearly impossible to continue to follow large numbers of people without clicking a button hundreds of times and scanning individual accounts to see if they’re legit. Refollow made this process extremely easy by allowing you to select large numbers of users you found interesting (e.g. following someone you like), and then curate those users with a series of helpful filters. For example, if I wanted to follow everyone who follows my favorite celebrity, entrepreneur, or investor, but I also want to filter out those users who haven’t tweeted in the last 90 days and/or have small followings (usually spam accounts anyway), I can do it within seconds using Refollow. And since many of those users will follow me back, I can quickly build a large and active following in just a few days.

To be fair, a service like Refollow’s could be abused, so it is understandable why Twitter would respond. But Twitter also wants users to build quality followings, which is very hard to do with Twitter’s native features, so Refollow is somewhat aligned to Twitter’s goals. Even more disturbing, however, is how quickly Twitter cut off the lifeblood of a company built on their platform. When Refollow opened their doors last year, the rules on API usage and follow counts were less evolved than they are now, but Refollow seems to have been treated as if they just started up yesterday and began helping people build massive followings (which, afterall, Ashton Kutcher taught everyone to do in the first place).

The rashness of this decision could also shine some light on how Twitter views certain services & businesses built on their platform. These products are quickly becoming a primary destination to consume the firehose of Twitter data (over even Twitter itself). This trend was the basis for our Seesmic prediction last month. Investors and entrepreneurs who are affiliated with innovative companies like Brizzly should take notice. Refollow was shut down without any major warning. Hopefully, Twitter will soon release a process that helps other companies avoid a similar fate.