Every now and then you do have to take your hat off to a new mash up.

This time the cunning people at Vodafone have hooked up with Ben Marsh who created the #uksnow map a few months ago. The new map uses Twitter hash tags to create a map that shows where Brits plan to take their 2009 holidays. 

The smart bit? You simply update your Twitter account with with the #ukhols tag along with a holiday destination.  But you are also asked to enter age, gender and postcode. Valuable data for Vodafone, which is using the site to promote changes to roaming charges this summer.

It's also significant that in the wake of the recent Harvard report into Twitter usage, one global organisation is using a smart campaign to promote an offer AND capture reliable Twitter demographic data. As Steve Ellis points out in his recent post, its all about understanding rather than broad perceptions.

Disclosure: Vodafone is a client, but not this part of their business.