soon yes, I have concerns about photos, particularly photos of children for reasons I'm sure you can work out. I have less concern about photos posted on threads, but any information - text or images - can be used by unscrupulous people.
When we sign up to GN we agree to the Terms of use which explain our rights, responsibilities and obligations when using the site. The Privacy Policy does say -
Security
We are committed to ensuring that your information is secure. In order to prevent unauthorised access or disclosure, we have put in place suitable physical and electronic procedures to safeguard and secure the information we collect online.
And that's all we can reasonably expect GN to do. But we have to decide how much information about ourselves and our families we disclose and I might be over cautious, but for me that means not disclosing information that could identify me or my family, or be used in an unauthorised manner. This is irrespective any security breach (which GN says has not happened).
GN is a very nice place, but as with any message board, unless we're meeting up with one another, we take each other at face (virtual!) value and that doesn't always work out well.
Posters on MN take their personal information and personal security very seriously and I do think some GN posters are too trusting about this. I am not a cynical person, although I do wonder if my age has something to do with my opinion because I suspect I am one of the younger GN members.