I’m an avid Gmail user, and have been pretty happy with the service in general aside from needing to get an invite from someone to get in. Google recently announced that you can sign up for a Gmail account using your cell phone. You then get a text message with an invitation code. I found myself asking: why is it that Google makes us jump through hoops to sign up for a free service? I came up with two answers.

First, they’re collecting user data. If you got an invite to Gmail, you had to have another e-mail address to receive it. Congratulations, now Google has your away-from-Gmail address (which you probably don’t use anymore, but whatever). If you sign up using your cell phone, they now have your cell phone and an e-mail address to contact you at. Anyone else scared that Google knows so much about you?

Second, which I believe is the main advantage of this system, is that it keeps spammers from signing up for hundreds of Gmail accounts. Such activity forever caused Hotmail to go onto blacklists for many years. By making sure that people have another e-mail address or cell phone, Google is effectively keeping out fly-by-night spammers. And even if one gets an account, the rapid proliferation can’t place without a lot of effort. You get invites only after you’ve used the service for a while, and those must be sent to existing addresses as well. It’s much more than viral marketing, it’s an ingenious way to keep the spammers out.