Demos vs Viewers: what gives?

I am SO tired of hearing about how the 18-49 demo is the only thing that counts. So I was quite pleased to read that actually, that's not the case. According to this article, (2001) the demo that really needs to be looked at is the 25-54 demo. Apparently, advertisers DO look at it when buying advertising time - not just the 18-49. So, the next time some one says the only thing that counts is the 18-49 demo, tell them that thinking is like, so ten years ago.

http://www.medialifemagazine.com/

Meanwhile, LAST YEAR, 2010, The Herald/Tribune had this article, exposing a dirty little secret: for all the hype in the trades about the 18-49 demo, business-wise, it's not the most important demo anymore! All the networks and advertisers seem to be aware of and working with the idea that the demo to be looking at is older. The population is older, but healthier, vital, SPENDING MONEY. They are also the ones more likely to be watching TV. So, maybe those most watched viewership numbers mean a bit more than the trades would have us think.

http://www.heraldtribune.com/article/20100817