activity purging plugin - another way of solving the problem of activity table bloat.
if you manually delete activity table or decide you want a plugin to purge old activity records that bloat your database.
if you liked the cleanlog plugin you may like this one.
when you look at the activity link - these are the entries that it purges.
note: even if you disable viewing the activity link, your activity table is constantly growing.
I may not provide the completed solution you might desire, but I do try to provide honest suggestions to help you solve your issue.