Wolfram Alpha now allows you to analyse your Facebook activity :)
It showed me I used it most at the first half of 2011, average 1.3 likes per comment and 1.4 replies per comment. It also shows I have hardly used it since 2011 2nd half and has analysed who has contributed the most on my Page!
As I mentioned, I hardly use Facebook any more but it's a cool feature. Download the fb app on Wolfram Alpha and try it yourself!