Dot-com. Wow: just saying that makes me feel like I’m back in the 90s.

There’s a new top-level domain coming to rule the Web, .CO, and it just registered a couple Silicon Valley heavyweights.

Google

Yes, the Mountain View, Calif.-based search classic and recent social media star announced Monday afternoon that it has acquired G.co.

The new short domain is to be used strictly for directing users to Google-owned products and services, meaning it will serve a separate purpose from goo.gl:

The shorter a URL, the easier it is to share and remember. The downside is, you often can’t tell what website you’re going to be redirected to. We’ll only use g.co to send you to webpages that are owned by Google, and only we can create g.co shortcuts. That means you can visit a g.co shortcut confident you will always end up at a page for a Google product or service.

Google launched goo.gl in 2009 as a public URL shortener, competing directly with the likes of TinyURL.com and bitly. It will still be available for that purpose.

500 Startups

The other organization going .co is Dave McClure’s not-just-another-accelerator, 500 Startups, also headquartered in Mountain View. Starting today, typing 500.co in your address bar will take you to the incubator’s official website.

“At 500 Startups, we focus on doing things faster, making cycle time shorter, and simplifying brand.. we know no one cares about your product if it’s not fast, easy-to-use, and memorable,” writes McClure. “We want to OWN the brand 500, and 500.CO helps us get there.”

McClure notes that the domain is not like all the others trying to rise to prominence, as it has already drawn over a million registrations in over 200 countries.

Others

Besides Google and 500 Startups, well-known users of the .co domain name are Amazon (a.co, k.co, z.ko), AngelList (angel.co), Overstock.com (o.co) and Twitter (t.co). (Oh, and don’t forget us: Vator uses vator.co for company profiles.)

Interestingly enough, .co is the domain assigned to the Republic of Columbia by ICANN (the Internet Corporation for Assigned Names and Numbers). The official .co registry is actually a joint venture between two organizations, Arcelandia S.A. and Neustar, Inc., which also distributes domain extensions such as .US, .BIZ, and .TRAVEL.