Move over Dell. You’re not the only company looking to turn social media into a medium for loyalty marketing.

If you wear shoes (who doesn’t?) and want to be part of an exclusive club of VIP shoe buyers, you have less than 200 minutes to become a Zappos.com VIP. Zappos.com, of course, is the online shoe retailer whose CEO, Tony Hsieh, has made extensive use of social media, namely through Twitter, where he has over 50,000 followers.

Now Zappos.com is leveraging its social media popularity to promote a limited-time offer – the Zappos.com VIP.

Zappos.com VIPs “get exclusive features and benefits available only to our VIP customers!

One major benefit being promoted: guaranteed free overnight shipping (within the continental United States).

Not a bad deal. But with less than 200 minutes left to go in this round of the VIP offering (Zappos.com started offering VIP memberships last month for short periods of time), you have to be quick.

And being quick is largely the result of being on social media services like Twitter, which is obviously the point.

Clearly, companies are getting more creative in using these types of services to extract value and build relationships with those who ‘follow‘ them, and in this case, Zappos.com is cleverly using Twitter to promote a program that results in registrations that it be stored in its own database.

And just as with Dell’s program, Twitter isn’t getting paid a cent.