They mentioned demographics a while back, telling everyone to put their dates of birth on their profiles. This was when they said Vox would be for older, less technical users, with LJ for the younger ones. Obviously it never occurred to them that their users get a year older with every passing year...

Still, check out the 3 or 5 year stats at Alexa...

http://www.alexa.com/data/details/traffic_details?url=http%3A%2F%2Flivejournal.com%2F

It doesn't look like LJ's dying there, and they're the kind of statistics advertises watch.