Spammers always have an identifiable footprint. Because they automated their process, you can either recognize their pattern or it’s simply obvious. Here’s a spam in the form of a Facebook friend invitation I received.
The confirmation message read:
Hi Danny,
I found you on a Malaysian group and I am expanding my Malaysian contacts for business and social purposes.
Hope you can confirm me as a friend in Facebook.
Sincerely,
[Name of Sender here]
It may sound and read as sincere and legit. However, I received 2 friend confirmations with the exact, word for word, confirmation message. It was totally identical except for the name sign-offs. Seriously, I’d not take this as a coincidence.

This experience is making me a little worried. Especially since Facebook did a major announcement on their privacy settings.
For this to have been automated, it could mean someone created a spam application or has hacked into Facebook and caused this. As much as it may not be the mistakes of the original account holders, I’d still report them as spammers.
Now, if only I could find the report spam button in Facebook.
Should be hacking case. This happened quite similarly during Friendster era whereby my friends ‘sent’ spam messages via inbox.