It is a TLD; a ccTLD (country code TLD). It will never become a gTLD (generic TLD) though. Clearly, by its cost, it shows the Colombian government can't afford to stand up to modern day gTLD prices of $10, so I doubt it can pay ICANN the supposed $185,000.
Also, it's too much like the .com, thus losing a lot of traffic and revenue for those sites that may use the .co extension.
Oh, but most of them will be worthless if there is an active .com version of it. For example, if there is a pro.com and pro.co, people are going to think of the .com before the .co, so there would be a major loss of traffic for the .co.
Large sites should register the .co and the .cm. They are common misspellings of the .com extension, so it would gain them added traffic.
I don't think it will take off. I can see many site owners being worried about the confusion with .com and therefore sticking with .com, .net, .org etc domains.