Well, actually, no.
I was regularly receiving emails which purported to be from someone I knew, but which were actually from Plaxo, in which Plaxo asked that I confirm my information and (in the process) tried to recruit me into providing additional personal information to Plaxo. I read their user agreement, and they consider any information provided to them to be theirs to use in accordance with the provisions of their terms, as they might be amended.
When I called the Plaxo guy, he could not understand why anyone would object to Plaxo data-harvesting in this way. I mentioned to him that I did not want to be added to their sellable database of names, and he assured me that "We'd never do that..."
...which is fine unless you remember that all promises made are readily broken in bankruptcy with the stroke of the judge's pen, and any valuable asset (like, say, a fully-validated list of people, companies, phone and email addys) will be sold to the highest bidder. Egghead.com had no intention of selling its customer database, but when they went baky, the lists were sold and used.