[DanBC]

EDIT: I am wrong. See Blowski's message below.

It's unsolicited, bulk, messaging and so it meets definition for spam.

I wonder if it meets Facebook's rules for acceptable wall posts or not. I can see some people hating it.

[blowski]

It's writing on the users own wall, which they are asking it to do. Therefore it's not unsolicited. It doesn't write on other users' walls, so it's not bulk.