This thread runs so fast I hardly can follow! Hopefully it's a sign about the importance of the matter in hand.
For what I've read and seen there seems to be two major issues: Low numbers during peak hours and low numbers during off-peak hours, both of which make people leave at least for the session they had planned to play.
There's a recipe so simple everyone can do it: Instead of leaving, stay! Wait for the numbers to grow. If everyone who currently only pops in to see some familiar names on the roster would stay for an hour or so waiting for the said names, the numbers would look entirely different! Also, you can inform others that you're going to play at a certain time. That method has worked wonders in the Finnish community, our three year old "Action for the flying night" thread is 36 pages long - not bad considering there's only about a dozen more or less active players here. That means a page a month, one message every second day on the average with 15 messages a page. Think about that, do some more math with the number of players in your squad.
As for advertising, I've never seen one. I also suppose that I'm not in a minority for not watching TV very much. At least that's what I've been reading: Active computer users don't have time to watch TV. They watch their computer instead, thus also being able to skip the annoying ads! For off peak hours the ads should be on the European channels, each country having their own. Investing into that would never pay back!
So, please do yourself and your fellow AH'ers a favor by staying online a little longer, wait for others to pop in. While waiting, do something you wouldn't normally do: Up a hangar queen, learn how to drive a vehicle or a PT boat, explore the surroundings with a Storch...