Ever since the dawn of twitter url shortening service has been a rage, first major player was http://tinyurl.com which operated as back as 2002 then http://bit.ly followed and was also funded a hefty $2 million once it gained momentum. Over the years we have seen much activity in this area.
Over all they have been able to secure a very short domain name which is the first achievement in this task this was a major blow to tinyurl.com when bit.ly because bit.ly had five characters less than tinyurl.com a major number if you have some tweeting experience.
Besides the basic url shortening service they have few useful features
Ability to add custom url so if i want to have a shortened url as per my own wish i would be able to do that so lets say i want to have a shorter url for this review I generated http://oo.ki/ooki_review
Password protection you could generate a url and password protect it, if you need to share it with specific people only you can use the password, i am not sure how practical this is but a feature none the less.
Similarly you can make your shortened url expire after some time or after a number of usages (so it should disappear lets say after first 5 people visit it) useful if you are having a contest.
Also they have provided APIs which would enable third parties to use this.
Over all they have thought through every thing and covered all areas how ever I don’t know if independent url services have a long term business value because all major services have started their own shortening service mostly because it gives them more control of their content and userbase.
twitter launched t.co, facebook has fb.me, google got goo.gl, stumble upon has su.pr. Because these major players have their own services the ultimate battle becomes of what the third party clients (tweetdeck, seesmic etc) and services use as a preference and they do have some choices around in August 2008 there were 90+ url shortening services what is the situation now is any one’s guess.
I wish these two people best of luck in their endeavors hope they make it big.