A new user in the Netherlands became the 60 millionth person to sign up with LinkedIn, the professional social networking site.

Facebook says it has 400 million users of whom half log in every day.

Both are fabulous tools for communications and socializing, but making members’ identities and personal information so easily available carries some big risks. Our good friends at Sophos have pointed out that information can be harvested from LinkedIn for spear phishing. The site can contain enough information to be a virtual company directory.

There are unexpected exposures too. Imagine linking to a recruiter you’re having conversations with and being able to see the other people he or she is linked to – like your subordinates – or your boss! That spills just a bit too much info on all of us.

LinkedIn story here.