Effective June 2, 2009, Apple is tightening their guidelines for their $99 per year One-to-One program.

As of June 2, the One to One membership will only be offered to customers who purchase Macs through Apple’s direct channels – our retail stores and the Apple online store. The price for the program will remain $99. Existing customers will be able to renew for one additional year for the same price as well.

What is it that’s driving Apple to tighten these guidelines? Is the program becoming too popular? Is this part of Apple’s strategy to drive more sales through their direct channels?

I’ve heard from various sources within the Apple retail channel that the program’s popularity has begun to grow exponentially. In fact, Apple had to re-word their verbiage about six months ago to reflect and communicate that one-to-one was subject to availability of time slots, according to one source.

What do you think?