I was checking out the new service (U.S. only) that allows anyone with SMS access to sign-up for a Gmail account and noticed that Google mentions that more SMS services are in the works. Specifically, secure password recovery and SMS mail/news? alerts are noted. Surprised? Hardly. Most of the other large web search services (aka Google competitors) already offer alerts (and other info) delivered via SMS. For example, I've blogged about traffic alerts from MSN. I'm also a regular user of Yahoo text message alerts (including mail) and receive baseball scores, video game news, and more on my phone from AOL.
Postscript: Russ Beattie correctly points out that by offering the Gmail sign-up via SMS they're also building a database of active mobile phone numbers.