From the Big Ten fan perspective, I'm not quite sold on GT, either, but I understand the rationale. People can't look at it as GT won't ever be as popular as UGA or that the Big Ten won't ever be as popular as the SEC in the Atlanta market. That is *completely* faulty analysis. The point is that if the Big Ten can just get an ACC-level of interest in the Atlanta market, it's pretty massive. Why? Atlanta might be the #8 TV market overall, but in terms of being a college football market, it's the most valuable one in the country pound-for-pound. The interest in college football overall there (not just for UGA) is unlike anything in any Northern market. It's not even close. That's probably the biggest education point that doesn't seem to be coming across clearly on these boards - I don't think people are quite realizing the size and scope of the chasm where being the #2 or #3 school in a market like Atlanta (or Florida or Texas) can mean much more than being the #1 school in a Northeastern market (even one that has a large population on paper). *Everyone* follows college football there in the same manner that *everyone* follows pro sports in the Boston market. In Atlanta, college football is the dominant spectator sport, so even if GT (plus UVA or whoever else the Big Ten might add) ends up with a smaller percentage of the overall viewer base compared to their SEC counterparts, that overall viewer base is massive (effectively the entire population of that market). Contrast this to, say, NYC, where college football is a niche sport, so you need to capture a much higher percentage of college football fans in a place like NYC compared to Atlanta.
Look at this list of the top 25 highest rated college football markets:
http://johnclay.bloginky.com/2012/08/29/the-top-25-television-markets-for-college-football/#
Atlanta comes in #5 on that list... and remember that ATL *dwarfs* all of those other markets listed in size, so the sheer numbers of people watching the sport in that market is larger on a week-to-week basis than any other place in the country. Read that list again and compare it to the top 10 overall TV market list someone had posted earlier. Atlanta is the only top 10 market that appears on the top 25 college football market list... and it didn't even squeak in at the bottom. It's at #5!
That's why the Big Ten is looking at Georgia Tech. Just as the New York Mets are the 2nd most valuable team in MLB after the Yankees (yes, even more valuable than the Red Sox, Dodgers and Cubs) because the NYC market is so important for baseball, even the #2 team in the Atlanta market brings a ton of value to any conference because that's the single best college football market in the country when you take into account both size (it's a legitimately large market) and fan interest (lots of people actually watch college football there - it's not just "potential").
Now, I think it would be a mistake for the Big Ten to just add on GT as a lone Southern appendage. If the ultimate goal for the Big Ten is to add all 4 of UVA, UNC, GT and FSU, though, then there's more than enough of a critical mass of alums in the Atlanta market where it's perfectly acceptable to be the #2 league in that key college football market compared to the SEC (especially when it's #1 in NYC, Chicago and DC on top of that, which the SEC can't compete with).