Luke Shaw is a name that's piqued the interest of many Chelsea fans. He's a dynamic left back, and his performances last season would have been impressive even if you forgot that he was a teenager. When you combine his obvious talent with the fact he's a Chelsea supporter, it's no wonder that many are looking at him as a potential successor to Ashley Cole.
But even if the club are looking at Shaw for the future, they're going to have to wait to pick him up:
Although we'll get headlines like 'Shaw commits his future to Saints,' signing the defender to a five-year deal doesn't mean that Southampton won't end up selling well before the end of the contract. It just gives them more leverage when they do decide to sell, and more leverage means more money in the long run. And it's good for Shaw too, since he gets a raise. Everyone likes raises!
In the short term, this should silence the Shaw to Chelsea chat for at least the next couple of transfer windows. But I wouldn't be surprised to see them kick into gear again next summer, especially if he has a strong second season.