I'd like to second both of these suggestions, as well as add a couple of my own...

Have you considered parsing the posts for links in the CB? I imagine it would lend itself to some very interesting correlations down the road:
"What percentage of posts link to cpan?
Which Monk links to his/her scratchpad most often?
etc..."

To make this really work well, you would definately need at least a time value as suggested already (and if you plan to keep more than 24 hours worth of data, a date value will be necessary as well).