I'll still maintain it won't get you near the limit -- if this columnist really did have a 25gb limit, the 2gb download was still just a fraction (he's been downloading a lot of other stuff, seems to me). So it's not time to start worrying yet -- if your ISP does send you a letter, then you can look at your internet usage, and see, if like this columnist, it's time to switch ISPs.
But he's got another point, and that is that gaming is clearly having a large effect on computers and technology in general. Would we be fulfilling Moore's Law every two years if we didn't have 3D graphics that needed upgrading? Would high bandwidth connections be as prevalent today around the world if it wasn't for games like WoW that required a high bandwith hookup? Gaming is affecting the basic technologies and economies of the Internet these days, for better or worse.