Vaeldras
Terrarian
I think you were playing on the wrong server. Mineplex, the biggest Minecraft server to date, has had over 25000 (yes, 25k) players on at one time, spread across all sorts of minigames, not just boring old survival.
I hate to say it, and yes I am defending Minecraft (because I play it all the time), Minecraft has Terraria beat when it comes to multiplayer. Minecraft servers have custom plugins so you can play Hunger Games, Hide 'n Seek, Team Deathmatch, Paintball, Capture the Flag, the list goes ON and ON. I realize that Terraria has plugins as well, but it will never be as advanced and popular as Minecraft servers because there is only so much you can do with a 2D game.
But that being said, Terraria is not "dead", people just become inactive because they are waiting SO long for a new update to come. Honestly, if 1.3 was split up into 3 or 4 different updates released sooner and continuously rather than later and just 1 update, I think it would be better for the community. That way we keep getting new content occasionally instead of bombarding everyone with 100 new things added at once, which can be overwhelming.
Minecraft multiplayer is pretty much the meaning of life.
The good old days when me and a couple of friends used to meet up at 3 am in order to "Tnt-cannon" the base of a group of guys who would have eventually rebuilt it during the next day