[Macha]

Did these contacts of the user give consent to be contacted? Your behaviour seems spammy.

Also the Google page states the following "We don't allow unauthorized publishing or disclosure of people's non-public contacts. " Arguably contacting these people is disclosing they are in a user's contacts. You do seem to breaching Google's policy.

I'm on Google's side here.

[heroic]

In that sense, isn't Facebook showing people you may know, also disclosing to people that they are in my contact list?

[Macha]

Contact book presence is but one input into that algorithm, which also incorporates friends of friends, friends of people who've logged in from the same IP, people who frequently interact with the same people/content. Its not directly "You might know Alice, we know because she has your number"