How much memory does MySQL need?

[Bill Todd]

I know, I know, with database servers more is always better.<g> However,
assume I need to deploy MySQL using InnoDB to multiple sites. Hardware cost
is a significant consideration. Is there any information available on
MySQL's memory requirements? Most database vendors give you something as a
starting point but I could not find any information in the MySQL Manual.

Can someone point me to a source?

Bill