Update: Google has added “.io” to the list of gccTLDs – thanks Google for the very quick response!
I will preface this by saying I am not an SEO expert – I am going off of a night’s worth of research on geo targeting in SEO.
When we decided to go with the name Clay.io, we weren’t thinking too much about SEO. It turns out it has had somewhat of an effect as “.io” domains are still considered ccTLDs (Country Code Top Level Domains) by Google, rather than gccTLDs (Generic Country Code Top Level Domains).
It would appear “.io” specifically targets the British Indian Ocean Territory (a series of islands in the Indian Ocean with a whopping population of 3,000) – much like .co.uk would target the United Kingdom. “If no information is entered in Webmaster Tools, we’ll rely largely on the site’s country domain”. (source)
Google doesn’t do this for all TLDs however:
Generic top-level domains (gTLDs) don’t target specific countries. If your site has a generic top-level domain, such as .com, .org, or any of the domains listed below, and targets users in a particular geographic location, you can provide us with information that will help us determine how your site appears in our search results. (source)
When it mentions “any of the domains listed below” it includes gccTLDs, an acronym Google seems to have coined.
These are the current gccTLDs that are treated as generic domains.
.as .bz .cc .cd .co .dj .fm .la .me .ms .nu .sc .sr .tv .tk .ws (source)
I’d argue “.io” in 2013 is more popular than at least 10 of those, so it would seem the list is simply outdated and someone at Google just needs this as a reminder to update it.
Does Google Even Control This?
They appear to have coined the gccTLD acronym, and that list of domains above is only reference by Google, so it would appear so.
How Much Does It Matter?
It’s hard to say because it’s a difficult thing to test. The information I found on the issue ended up contradicting itself, mostly because Google keeps their ranking algorithms a secret, so the “SEO experts” speculate a whole bunch (which I suppose I’m doing as well). The easiest way to prove it matters is simply the fact that gccTLDs exist. Google decided to create a subcategory of ccTLDs for domains that tend to be generic (global).
Even if ccTLDs and gccTLDs were treated exactly the same in terms of ranking, Google does not take into account the Geographic target set in Webmaster Tools. Own a “.io” domain and want to target towards US searchers? It doesn’t work.
I wanted to come up with a good concrete example of the effect, but that’s difficult to do. The reason this all came about is I was a bit perplexed when Socket.IO didn’t show up on the first page of Google search results for “WebSockets”. I think it’s safe to say most developers who use WebSockets associate the term with Socket.IO since it provides easy integration, and some helpful fallbacks. Despite that, it is 19th in the results for “WebSockets”. Again, since I don’t know all the factors, I have no idea how much that would differ if “.io” was a gccTLD – but it appears to have an effect.
Companies Using “.io”
GitHub*, Filepicker, Codepen, Socket.IO (LearnBoost), Sencha*, Pen.io, Redis, Forecast, Intercom, Put.io, Customer.io, Trigger.io, Keen.io, Filecloud, and many more.
The TLD has become common for development related sites, initially because it’s an acronym for Input/Output, but more recently the popularity is probably due to herd behavior. Unlike .tk domains which are free (and actually gccTLDs), .io domains cost anywhere from $50 to $100 per year, so that filters out the junk pretty well.
If you know someone who might be able to help with this at Google, I would appreciate it, and I’m sure the founders of other “.io” companies (Filecloud.io, Filepicker.io, Codepen.io, Forecast.io, Intercom.io, etc…) would too.
Another to take action would be to make this appeal more visible to others – tweet, vote up on Hacker News, Reddit, etc…
One final way to possibly draw attention to this would be to rate this Google article as “Not helpful at all”, perhaps that will flag it for Google’s attention.