
Introduction
Sharing links is a vital aspect of Twitter that bloggers use every day. It is a great way to spread your content, and when done properly can expand readership, build brand, and provide value for your followers. Since sharing links can be so important, it is important that you use the right URL Shortner at the right time.
URL Shortner? What’s That?
Twitter only allows you 140 characters for you to get your message across. Since you are promoting a link, you will want all the room you can get for “the pitch.” Some links can be rather large(even 140 characters themselves) and the solution to this is a URL shortner. A URL shortner will take your existing link and convert it into a nice, clean package that is far shorter in terms of characters.
Examples of URL Shortners
Tinyurl
is.gd
snurl
Not Long
Tweetburner
When to Use Tiny URL

Tiny URL is most likely the most branded URL Shortner around. Twitter uses tinyurl as their default URL shortner, and thus, most of your readers will probably recognize tinyurl over all the other options. If you have the room to fit a slightly longer link, then use Tiny URL.
When to Use is.gd

is.gd is less known than tinyurl, but in my opinion it does the job better. I mean when it comes down to it, tinyurl.com has 11 characters, and is.gd only has 5. Those 6 characters are important! The only downside to is.gd is that it doesn’t have a .com associated to it, and sometimes followers may not understand or even be afraid of is.gd. I wouldn’t use is.gd unless you desperately need the extra characters (which does happen from time to time).
When to Use Snurl

Snurl is a great URL shortner and is the default url shortner of the popular twitter desktop application Twhirl. If you are a user of Twhirl, using Snurl is EXTREMELY easy and highly recommended!
When to Use NotLong

Not Long is an interesting service because all the other shortners on this list randomly generate your links while Not Long allows you to name/brand your links.
For example, if your blog post is about tips for increasing RSS subscriptions, your link could be: “increasing-rss-readers.notlong.com” or something to that extent.
If you don’t need much room to pitch, I would highly recommend using notlong to brand your links with vital information about your blog post.
When to Use Tweetburner

Tweetburner is interesting because it tracks clicks. If you have a link that you feel will be clicked on a lot, then you may want to use tweetburner for it’s marketing purpose. On the front page of tweetburner there is a list of top 10 links of the hour, you may be able to pick up a few extra eyeballs if your link is popular enough to crack the top 10.
Conclusion
URL Shortner’s are a blogger’s best friend. Amazingly enough there are certain situations where certain services work best. I highly recommend testing out all the URL shortners and tracking results; remember that a certain readership may respond to a certain shortner!