I have been a steady user of Apple's online services since January 13, 2000. That's the day that Apple launched iTools, a collection of apps and services the company released to capitalize on the then-new fad of hosted services. With iCards, Web page hosting, e-mail and storage, iTools didn't let you do a lot, but it was a window into where Apple would go in years to come.
Of course, iTools before with the release of the iPhone last July. Even .Mac gave us a glimpse into the future of what the service would become--iCal sharing, backup and IMAP e-mail for all users that paid the $99 a year fee.
You might remember that there was a huge uproar from iTools users at the time of that transition, because those services had been free while Apple started charging for .Mac. Even with the uproar, I paid up and have been a customer ever since.
As a matter of fact, I'm not the only one in my family that has a MobileMe account. My wife has an account (also brought over from .Mac) and our two kids have e-mail only accounts (used for e-mail and to buy a ton of music and videos). The interesting thing is that my wife and I use the service in completely different ways.
I use the syncing services a lot. I've set it to automatically sync all of my information from contacts and calendars to e-mail rules and keychains. And it gets used a good amount, too.