I didn't jump on the .CO bandwagon and I'm not sure whether that's a good thing, or a bad thing.
I think I only got two of them, one was to redirect, and one because.. Um, I guess because just in case ;)
I do see some potential in the extension, as well as some negatives.
The negatives are, .CO is very similar to very popular .COM, so when someone sees a URL with a .CO extension, be it on a poster, sticker, newspaper ad etc, chances are they will just assume its a .COM! Even for those that notice, or see that the "M" is missing, I think a lot of them will assume that its a mistake.
These assumptions will eventually be corrected once the .CO extension is more widely known by the general public. Until then, it will be difficult to brand a new site in the .CO extension.
One of the ones I got was the .co version of my .com site which gets a lot of direct and type in traffic, so any typos will get redirected (I also have the .net .org .info etc).
I got the .co on the 28th of July and since then have had 140k direct visits to the .com site. I know a lot of these direct visits probably come via browser bookmarks, but some come from type ins. And if they type in the wrong extension, the redirects show up as referrers in Analytics.
So far I have had "142" visits redirected from the .NET, "14" from the .ORG and "1" from the .CO. That "1" was me checking that the redirect was working.
So I don't think .CO domains will get too much "typo" type in traffic.
The main benefits I can see with this extension is for SEO, because you have a better chance of getting your keyword domain in a new extension, and (if they take off) as an alternative to an unavailable .COM that's undeveloped but for sale (at an astronomical price) .
There are a lot of great .COM keyword domains out there that have not been developed, they just have a for sale sign on them. Often they remain for sale for a long time because the owners think they are worth more than the market is willing to pay (or they are holding on to them till the market catches up to their expectations).
Because the domain is undeveloped and basically just a for sale sign or sometimes a crappy niche directory, it gets no traffic and is therefore no competition. This is where the .CO has potential to shine, it can be built up, branded and rank in that niche without any competition from the .COM... providing the owner is an end user or is willing to brand and develop.
If it gets parked with a for sale sign on it as well, then it just becomes another wasted domain... unless of course the owner has realistic expectations about its worth.