LinkedIn is accused of doing this, or something similar. They badger users to give their e-mail addresses and passwords :eek: then harvest all your contacts from your e-mail account. Then send invitations in your name to all your contacts, to come and join LinkedIn. (I myself have received some of these.)
HuffPo article: LinkedIn Sued For ‘Hacking’ Users’ Email Accounts To Spam Friends
Bloomberg article: LinkedIn Customers Allege Company Hacked E-Mail Addresses
The Independent article: Stranger danger? LinkedIn denies ‘hack and spam’ attacks on members in marketing tussle