It would seem that Badoo have recently been harvesting the
address books of those with gmail and googlemail accounts, and then
using the harvested e-mail addresses to send spam.
This came to light when I received an e-mail purporting to have
come from a friend but when I queried the e-mail it was confirmed
that his address book had been harvested.
I made some further checks and it looks as though the Badoo site
is also involved in phishing. This phishing was confirmed when I
went to the site and was repeatedly requested to enter credit card
details in order to change some account settings (obviously I
didn't give any real details).