You setup the email notifications to suit you in "Your account" when you sign up.
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When should we send you email?Would you like to receive emails when invitations and notifications are sent to you in Flickr? (For example, when someone invites you to a group.)
Yes
No
Would you like to receive emails when someone makes you their contact?
Yes
No
Would you like to receive email when people send you personal messages in Flickr?
Yes
Yes, but only if they are a contact of mine
No, not at all
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I only receive emails that pertain to flickr, such as comments on pictures, new pictures from my contacts etc etc.... you can opt. out of all of these if you choose. The only emails i receive apart from these, are the ones asking me to renew my account.
Theres is zero marketing on flickr as far as i can tell, but thats not to say they dont know my neck size and inside leg measurements.
You can also stop your images being crawled by google and other search engines too if you wish. You can also completely block your photostream to the world except your contacts that you add.
It seems fairly sound to me... FB on the other hand... i'd agree, its a marketing and data hoarding exercise!
Rich