conservative use of module recommended

Issue Summary

There does not seem to be a more appropriate place to share this experience with the Yahoo_Terms module which, I submit, would suggest that people be very conservative with their configuration for this module.

I configured the Yahoo_Terms module to extract 20 terms for all existing nodes quickly building the table size to over 80,000 records. With more than 23,000 hits on the database today each searching through those 80,000 records in the terms table (amongst all other tables) and returning just 20 results per node caused my MySQL demon to drive CPU usage to over 80% which aroused some justified consternation in the offices of my ISP.

It may be appropriate for the developers of this excellent module to refer to this story somewhere in the module documentation to warn others of the possible consequences of unbridled term extracting...