It's not just Windows. OS X phones home too.

Daniel Jalkut has discovered that Windows Genuine Advantage is not the only OS software that phones home to check in. Mac OS X 10.4.7 does too. Using Little Snitch, an app that monitors network traffic on your Mac, he caught OS X phoning back to Apple HQ.
Daniel Jalkut has discovered that Windows Genuine Advantage is not the only piece of software that phones home to check in. Mac OS X 10.4.7 gets lonely too.
Using Little Snitch, an app that monitors network traffic on your Mac, he caught the home-sick culprit, a new Dashboard process called dashboardadvisoryd.
Every now and then it "phones home" to Apple to check that your Daskboard widgets are up-to-date. At least that's what Apple says in its 10.4.7 release notes.
The important issue here, Jalkut notes, is one of transparency. While nothing untoward is going on, it is still that process is hidden, operates without telling the user what it is doing and can't be turned off:
In an era when consumers are being encouraged to take responsibility for their own safety in the interconnected world, Apple and others should respect the boundaries of our "digital house" by at least keeping us in the loop about what is being done on our behalf. I can find no documentation about what Apple is choosing to send and receive on a regular basis from my Mac. Keep me in the loop, Apple. And if I’m not comfortable with it, give me an option (short of Little Snitch) for turning it off. It’s my computer, after all.
UPDATE: Cult of Mac has worked out how to turn the daemon off.