Sprint has joined Verizon and Alltel in their decision at least to delay their decision to participate in the nationwide wireless 411 directory - a service which would allow consumers to opt-in to the service as opposed to paying to opt out like many landline services.

The service - to be offered by Qsent already faces a number of challenges beginning with the need for consumers to opt in rather than out and including recently passed legislation in California which requires the carriers to obtain written consent from the consumer before being allowed to include them in the list.

With ARPU's flat, carriers are certainly in need of incremental revenue opportunities, but I don't think they'll find a big win in wireless directory services. Cost is one hurdle, but consumer interest is an even bigger one. Mobile phone numbers remain "guarded" by many individuals - a piece of personal information to which individuals like to control access. JupiterResearch shows that consumers are interested in Directory Services (411) - in fact these services top the list of productivity services that interest consumers -, but they are primarily interested in pizza delivery, tow trucks, and taxi's - entities with landlines.