Mac OS X Tiger is full of features you never notice until someone is looking over your shoulder saying, “What’s that?”

In this case, Joseph was looking over my shoulder and what he noticed was an accidental drop down sheet in Address Book that led me to realize that Address Book supports address book sharing through dotMac. I don’t think I ever saw it mentioned but is interesting given who I work for.

This is a sheet that pops up when you select “File->Subscribe to Address Book…” from the menu in Address Book. I had no idea it was there until today.

A quick perusal of the Help Viewer yielded these two gems:

This is the help page on how to Share your address book with others through dotMac. Click image for larger view.

This is the help page on how to subscribe to antoehr person’s address book. Click the image for the larger view.

I haven’t had a chance to try it out, but it seems access control is managed entirely through dotMac. This means both people need to be paid subscribers. Also, there appears to be no way to specify a subset of your address book to share. These things combine to really limit it’s usefulness.

Still, the idea of Address Book sharing is a good one. I hope Plaxo implements it in the future in a manner that overcomes these two deal-killers without losing the Mac ease-of-use. Right now all you can share right now is your own contact information and only if you want to. Plaxo really values security and control so neat things like that take a while to develop.

Anyone have any ideas, comments, questions? Our product managers are sure to read this blog entry because their blog search engines will nab this.