Plaxo and privacy

[Jim Shimozawa]

Anyone on this list know anything about this address book application?

This morning I got an e-mail from someone I'm doing business with 
(first time) on eBay
asking me to update his address book with Plaxo.
Granted, expanding one's business network is a good thing, and you're
asked to give as much or little information about yourself. And I'm 
told that

"Your information is stored in my personal address book and will not be 
shared with anyone else".

Am I being overcautious?
What would you do if you were in my shoes?

Jim