The concept of TV Everywhere is simple: it’s “supposed to let you watch whatever you want, wherever you want to watch it, on any device you want — as long as you pay for TV,” writes AllThingsD. But behind the straightforward idea, cable companies have been struggling for three years to get it done — “and they still can’t really deliver,” suggests the article. But startup NimbleTV says it can do the job.

Customers pay NimbleTV a monthly fee and they promise to deliver TV over the Web to any device the customer chooses. “You’ll still have to pay for cable TV (or satellite TV, or telco TV), but then they’ll get the video to you, wherever you are,” explains AllThingsD.

But the work being done behind the scenes is more complicated. “Rather than connecting to a set-top box in your home, Nimble plans to set up accounts from different pay-TV providers at its own facility, then move the TV signal from those pipes to the Web,” according to the article.

CEO Anand Subramanian will offer the service for free to at least 250 users in the New York City area before launching the product in full during the first quarter of 2013. He’ll likely charge $20 a month at that point.

“That fee will be on top of whatever a Nimble user ends up paying for TV — this isn’t a service designed to help cord-cutters. But if it works, it will at least deliver on the mobility and convenience promise that the pay-TV guys have been talking about for a long time,” notes the article. “At least as important: Nimble could encourage competition between pay-TV providers, since users aren’t required to sign up for a pay-TV package that’s offered in their neighborhood.”