Excellent idea - surprising this hasn't been done until now - in fact Nef, even though it's 3x as much work and a PITA, whoever is running the FB page should also sink claws into Twitter (even though they SUCK but that's another post in oclub), Instagram, and Twitch, and do the same with the alerts with each social media system. Very timely with the new version's landfall within sight now.
Instagram for pics of events, Twitch for streaming them, and Twitter for those who use it and not FB, or just to "double up" the chances of alerts being seen by both players and potential new ones. Youtube would be a good place to work as well, in conjunction with Twitch. I think a lot of WT/IL2/DCS/ETC players and other WW2 interested gamers that don't even know HTC exists would come check out AH2/3, if they happened upon a Twitch stream of an event, or even really good Youtube videos.
More players should be the goal of every current player, not just HTC, as IMO more players = less problems in terms of common complaints such as "maps too large" and "difficult to find fights". Full arenas squash both of these primary complaints - mostly, hah.