I think it would be a good idea to have a button at the bottom of every Post to make it easier to report SPAM.
That could probably be associated with a sorting system at the other end so that SPAM reports are nor mixed up with other ReportToModerator issues. I suspect that would simplify things for the MODS.
Note I am NOT suggesting that a Post should be deleted as SPAM just because I report it as SPAM.
Riva:
Maybe better to put the button in the 'Report to moderator' page and add a few more default actions like wrong forum, off topic etc.
I think the other options require more info than just clicking a button - certainly if I think a post is in the wrong place I always make a suggestion for the correct place. I hope that sometimes saves the Mods time.
By having the SPAM button visible under a Post it sends a message to everyone that spam is not wanted,
A even better way would be to include a drop down list after Report to the moderator button is pressed, which would list options like wrong forum, wrong topic, unnecessary etc.