Your comments

So often websites are lazy and have a generic title for all their pages.

I have some in mind where it would be great to have a rule to regex match the URL, and then set the tab title for that - especially if part of the URL could be included in the title.

A really posh solution would also allow a cascade of rules (with a continue or end option when each matched) - that would allow me to change all those "|"s to "-"...    :-)