Rising along with the popularity of Twitter as well as other instant messaging services with character limits are services for URL shortening. There are hundreds of services on the Web for this, letting people use the smallest space possible for sharing and linking to content. Some of them generate shorter links; some come with bars at the top of the application; some are content to let their links expire. Standing out among all these URL shorteners, however, is Bit.ly, created by John Borthwick of Betaworks.

After serving as the default URL shortener for Twitter during the most part of last year, Bit.ly grew to become a web-wide tool. In December, Twitter stopped using Bit.ly, but this breaking of ties hasn’t stopped the URL shortening service from continuing to scale and serving as a useful tool for users, publishers, Internet marketers and eCommerce providers.

Still need convincing that Bit.ly is the URL shortener for you? Here are the top 6 reasons why you should use the service.

1. Bit.ly is bigger than ever

Bit.ly finds strength in numbers, and if you look at the service’s most recent stats, you’ll realize that the numbers are staggering. Its growth and reliability is no longer dependent on Twitter. Bit.ly shortens 50 million URLs a day, including content published on the domains of its paid service subscribers (like the New York Times and Amazon). In January, it shortened a total of 2.5 billion links; this number spiked up to 2.7 billion in February and 3.4 billion last March. Bit.ly is now officially 40 times larger than it was a year ago.

2. Bit.ly isn’t just for Twitter

The service is still big on Twitter, no matter that it has stopped being the microblogging site’s default URL shortener. More importantly, Bit.ly has 50% of its links shared outside Twitter. Last month, for example, more than a hundred million Bit.ly clicks went to another popular social media site: Facebook. Bit.ly’s bookmarklet also allows users to conveniently share their Bit.ly links easily on Gmail and E-mail.

3. Bit.ly’s supports businesses, marketers, and content publishers

The great thing about Bit.ly is that it enables publishers to keep a close eye on what’s happening with their links – both on the Web and across the social media landscape. People can actually track real-time click-through numbers and referrers so they can see what kind of traffic their shortcuts got and from where. In short, it compiles a lot of useful information about something as simple as a link. This information in turn benefits and supports the content distribution efforts of Bit.ly business clients, marketers, and eCommerce sites, all of whom are all looking to share and track their most viral products as well as create buzz around their products and services through Bit.ly.

4. The Bit.ly API is packed with a staggering feature set

With Bit.ly’s developer-friendly API, we can expect even more functionality for the service. There’s already the Bit.ly Twitter Search that lets users find links shared on Twitter, complete with associated traffic data. In addition to that, users can access link data generated outside of Bit.ly: several Twitter clients, for example, like Tweetdeck and Twitterfeed, allow users to enter their Bit.ly credentials so they can track their own link data. Moreover, adding Bit.ly functionality to any other web application is pretty easy. People can use it in a sidebar, for mobile, and even as a bookmarklet that slides out to show traffic, conversations, and history data.

5. Bit.ly isn’t just a URL shortener

It’s also a trend management and social media analysis tool. Marketers can create and execute their campaigns based on the data that Bit.ly provides. What are people reading and sharing and clicking?  With its tracking abilities, Bit.ly can actually become a very powerful tool for indexing the social web. Pretty soon everyone would be able to track the hottest links, the most shared videos, even the viral campaigns that brought in the biggest ROI – not just on Twitter, but also across the vast social media landscape.

6. Bit.ly can serve as a marketer’s ad server

Lots of marketers and businesses leverage social media in order to maximize their Internet marketing campaigns. With Bit.ly, they can access data – even do lots of testing – to make these campaigns even more effective. Because this URL shortener service mines data from created Bit.ly links, it becomes easier for marketers and businesses to create new revenue opportunities as well as analyze information like, say, average click rates or the best times to share a link.