I had one linkshell until we hit the max number of members (128). When that happened, we moved to a new linkshell. Out of that 128, about 40 of the active members transferred to the new LS. That was a couple of weeks ago. Now the LS is sitting at 72 members and counting. But they all seem to be pretty active. I also know that some of thee people who have joined the LS are in more than one LS and probably joined ours because they heard that we are active and welcoming.
So I don't know that we're getting an influx of people into the game. People are just moving around, or creating new characters, etc.
I agree that people may be just moving around across LS, but other than that, I know I have observed much more people between November and January, at least on Figaro.
Seriously, if I'm not at camp exactly at the hour I'm almost sure Behest will be full and I won't be able to get in, especially at rank20 camps.
Keep in mind that the there is a lot of variation through time in the number of people logged on, and I think that the active players may not play as intensively as in other games due to the state of the game, but my feeling is that the overall number of players has increased in the past two months. Granted I can't back this statement.