For ages I’ve been plagued by people who send (via Plaxo) those annoying emails saying “Please update your information…”, which has always had the added sting in the tail that it said “Join Plaxo now!” – while the program was resolutely Windows-only.

Plaxo, in case you’ve somehow escaped its curse-at-secondhand, is a sort of address book system that works both online and off. I think. It also seems to want to be social software (“Join Dan’s Plaxo network!”). Mostly I’d thought it only one step away from spam.

Now however I notice that there’s a Mac version which enthuses

The Plaxo Toolbar for Mac synchronizes your Mac OS X Address Book with your Plaxo Universal Address Book. Wherever you install a Plaxo toolbar, your address book will be consistent and stay up-to-date automatically. You can also access your address book on the web through Plaxo Online.

Err.. OK, except that (1) I sync the contacts I need with my mobile phone – far more likely to have my mobile phone with me than to have access to a computer yet not have my mobile. (If I were determined enough I could get the two to synch regularly through a cron job.) (2) if you pay for .Mac, as I do, then you can put your address book online already. (Though equally, why not just export it as a CSV file or HTML table and upload it to a password-protected page on a site you own or use? Hmm?)

What I’m saying is, I don’t get the point of Plaxo on the Mac. Can anyone enlighten me, or are my prejudices on this correct?