Free, ad-supported directory assistance has gone from the hypothetical growth engine for mobile ad revenue in some analysts' forecasts to a marginal segment in the mobile ecosystem. The largest and most visible provider historically has been Jingle Networks' 1-800-Free-411. However I suspect that call volume growth has stalled there.

That's what I surmise is behind a new contest to attract usage:

The nation’s leading provider of free directory assistance, 1-800-FREE411, announced today the launch of a “30 Days of FREE411” sweepstakes. Beginning November 1, 2009, every person who requests a phone number from 1-800-FREE411 has a chance to win $411 on the spot, with two randomly selected callers awarded the cash prize daily. In addition, every caller in November will be entered into a drawing for a chance to win a trip to Boston and a shot at the grand prize of $411,000.

At the beginning of December, one lucky caller will win an all-expense trip to Boston for two. During their two nights in Boston, the winner will play a game where they choose one cell phone from 411 available phones. Each phone is awarded a value and the winner will walk away with a minimum cash prize of $4,100, with one of the 411 phones valued at $411,000!

The major carriers initially announced free, ad-supported initiatives (i.e., Verizon, AT&T) but they've been neglected because ad-supported DA hasn't taken off and their traditional paid businesses are cash cows -- though with declining volumes. 

The chart below reflects that despite having access to the Internet on a mobile device, a large number of people see 411 as a resource they'll continue to use. However smartphone users tended to agree with the statement in larger numbers.