Interesting study on Facebook user activity.  May be wise to consider tweaking your status update schedule so you can attain more impressions & better feedback rates.

Takeaway #1: Morning posts perform better.

Takeaway #2: Users are more active at the top of the hour.

Takeaway #3: Weekdays are busiest, Wednesday especially.

source: http://www.huffingtonpost.com/2010/10/28/facebook-users-most-active_n_775505.html