There are so many annoying things about Plaxo - and other address-book update services like it - that one scarcely knows where to begin. So let's just dive in.There are so many annoying things about\u00a0Plaxo\u00a0- and other address-book update services like it - that one scarcely knows where to begin. So let's just dive in:"This is the second Plaxo message you've received," reads the boilerplate come-on included with each request for updated contact info. "Get Plaxo to automatically handle these messages." The last few words are a link you can follow to sign up for the free service. If you're a user - part of the Plaxo club - these information exchanges occur under the covers and spare you the extra in-box clutter that nonmembers endure.In other words, that come-on isn't just an offer; it's also borderline blackmail. They're essentially saying you can either sign up for Plaxo or resign yourself to receiving these unwelcome interruptions from everyone who a) uses Plaxo; b) has somehow acquired your address; and c) lacks any sense of e-mail etiquette.Yes, Plaxo offers nonusers opt-out options, including one that purportedly will protect reluctant participants from any and all Plaxograms. But\u00a0as has been noted here before, opting out of such propositions is time-consuming and carries the risk inherent in dealing with an unknown quantity.Another distasteful element is that so many of the requests for updated information come not from friends and business associates, but strangers who through some Kevin Baconish Six Degrees of E-mail Separation have managed to collect your address.The one referenced above was from a Gartner analyst with whom, near as I can recall, I have never spoken or exchanged e-mail. Yet the subject line of his Plaxogram read: "Keeping in touch." . . . How touching.So I sent the fellow an e-mail asking a few questions about his experiences with Plaxo and thoughts on the etiquette issues. He didn't reply to my request . . . and I won't belabor the irony.These services are selfish. The users get to keep their contact info perpetually up to date - no fuss, no muss - and all it takes is a willingness to impose on everyone they know, lots of people they barely know and some they couldn't pick out of a police lineup for reward money.If Plaxo users want to exchange contact info - or every intimate detail about their lives - with each other, well, more power to them. But pinging everybody in your address book is just a bit too promiscuous for my taste.Of course, the real bottom line with these services is not making the world a more efficient place through accurate address books; it's making money."Plaxo plans to make money by releasing business editions that include extra features (such as collaboration)," says Rikk Carey, the company's vice president of engineering, responding to\u00a0a string of unflattering comments on a Network World Fusion forum. "The free version will remain free, but we will be adding more and better new features to the premium versions."I sent Carey an e-mail, too. He replied promptly and promised he'd get back with answers to my questions after dispensing with a more-pressing matter. . . . He didn't. . . . More irony.Security and privacy concerns cling to these services like a 2-year-old child to a parent's pant leg, and Plaxo\u00a0goes to great lengths to allay those fears\u00a0on its Web site.Nevertheless, something tells me these services are going to have their work cut out for them selling the concept to network professionals. I asked one of our IT guys what he thinks of Plaxo. His reply: "You mean the one that updates your contact list? The guy who invented that stupid thing ought to be shot."Just a figure of speech, of course, but you get the idea.Oh, and my address hasn't changed in five years: email@example.com.