I use MS Outlook 2003's rules to sort notification e-mail from a bug reporting system into different folders, one folder for each combination of product and major customer. Each message is sorted based on a keyword in the message subject or body. Sorting by product name easy because it is a sub-string in the subject. Sorting by customer name requires a rule to examine the body of message and find a string whose pattern is release: <version> <customer>. Here's a simple regular expression to match this string:
release: ... name (assuming that version numbers are always in the form x.y).
But I got ahead of myself. After a fruitless half an hour, I realised that Outlook 2003 rules don't support regular expressions, nor do they support wildcards, for pattern matching. If you can find a reference, please send it to me.
Rather than spend more time hacking a VBA script, I just created rules that matched the product name in the subject and the customer name anywhere in the body of the e-mail. These rules work almost all the time, and only fail when someone enters the customer name somewhere in the body of the e-mail, which is different from the release name generated by the bug reporting system.