User controlled html title tags

What are the best practices for allowing a user to maintain the html title tags of all the major pages of his/her site?

One way could be to allow the mapping of URLs to some text.

For example, we have an app with the following (most complex) url format:

http://lang.example.com/searchpage.zaf?a=foo&b=bar&c=RANDOM

There are several parts to this:

• Language sub domain
• Search page
• Static parameter 'a' (user may want this in the title)
• Dynamic and relevant parameter 'b' (user may want this in the title)
• Dynamic parameter 'c' which can be ignored

Never done this before, so I'm asking how you would tackle this!

I handled the one to one mappings via a look up table which is managed by the user and the other features with code.