Remember Yo? Of course you do. Well, the single-button, zero-character communication tool that hogged headlines for weeks has just announced Pete Cashmore and Betaworks have participated in its $1.5 million seed-stage round.

Betaworks, a seed-stage VC firm and startup studio based out of New York, made a separate announcement earlier today. And it seems that John Borthwick, CEO at Betaworks, has been a big fan of the service for months.

“At the end of May, Matt Hartman invited Or Arbel, the co-founder of Yo, to visit Betaworks, and we started using the Yo app,” he says. “Since then, Yo has become part of our communications flow at Betaworks and in my life. We Yo with co-workers alerting them that a meeting is starting, I Yo with my wife as a hi during a busy day.  I Yo with friends, without any more expectation or need than a Yo back.  I get Yo’s from services that I am interested in tracking without having to download their apps.”

On/Off

It’s the on/off simplicity of Yo and its associated API that seemingly appeals to Betaworks here, with Borthwick noting that more than 2,000 developers have already started working with the API. “It’s a new class of apps…and as always Betaworks is excited and ready to take a plunge into a fundamentally new mobile expression and join the seed round of funding in Yo.”

There are some other big names on board that aren’t being revealed yet, but Mashable founder Pete Cashmore’s involvement is an interesting one too.

While it was already known that Yo had notched up around $1 million in early-stage funding, today officially completes the deal, and bumps that original figure up to $1.5 million. Not bad at all for an app that only lets you say ‘Yo’.

“The value of this round goes far beyond the dollar amount that we received,” explains Yo founder and CEYo (yes, seriously) Or Arbel. “Bringing such incredibly smart, talented, and experienced people into the Yo team at this stage is an incredible advantage that will allow us to accelerate the growth and provide more and better value to our users.”

➤ Yo | Betaworks