I would think that 'information' is already in the database.

You should probably only have to write something that simply queries the database for the info you want.

That way, you run the report only when you want it, you can control the parameters (dates, forums, etc). The great thing about having everything in MySQL is that it is all DATA, ready to run a report for analysis anytime you want.

Having a log file created would just be useless redundancy redundancy.