C/D if I feel the message is genuine, I'll reply or if it's an old friend and I am fully supporting them I reply otherwise I just plus and go on with my day lol
I only plus spam if it
-Addresses me
-It's for a survivor group game and the person really needs it
-is a friend
-someone who if i had ever spammed then that they plussed it.
And I usually don't reply unless I want them to know I plussed it.
if i get like 10 spam mails in like a minute from posting a blog, i won't plus any of them and i'll just mark them as read (unless one of them is from a friend).
and it depends how i'm feeling lol...sometimes i'll plus and respond w/ "+13," and sometimes i'll just plus and not respond :P