I think it would be useful to distinguish between well-intentioned but off-topic questions and those meant to promote a service or advertise a particular product. Is there a way to give advertising its own radio button in the "close" menu?
Why does the list of reasons to close a question include neither astroturfing nor spam?
\$\begingroup\$ Seeing spam like this (hopefully a dead link soon) makes me want to remind people, flag don't downvote. \$\endgroup\$– C. RossSep 6, 2010 at 11:57
\$\begingroup\$ What is "astroturfing" in this context? \$\endgroup\$– LeguRiSep 7, 2010 at 15:14
2\$\begingroup\$ "Astroturfing" is a play on "grass-roots support;" it refers to discussion threads started on fora with an ulterior motive, like engendering discussion of a game that is (secretly) produced by the poster. \$\endgroup\$– JadascSep 7, 2010 at 19:32
The flag list includes spam. I think flags are reserved for poor behavior -- there's a qualitative difference between someone who asks a bad question with good intention and someone who's trying to abuse the system, as you note.
\$\begingroup\$ Got it. I hadn't really explored the flag list; I'm finding the features as I stumble over them. \$\endgroup\$– JadascSep 3, 2010 at 12:02
\$\begingroup\$ Can 2000 rep delete spam Bryant? \$\endgroup\$ Sep 3, 2010 at 12:04
2\$\begingroup\$ I can vote to delete it, but it's only one vote. I believe the big thing that separates moderators from high rep people is that moderators can close/delete/etc. single-handedly. \$\endgroup\$– BryantSep 3, 2010 at 12:12
2\$\begingroup\$ If a question is flagged enough it will die automagically. If you post it here on meta or on chat, we'll usually dog pile it into oblivion. \$\endgroup\$– C. RossSep 3, 2010 at 14:05
You should flag spam, not vote to close.
You have a limited number of close votes, don't use them up on spam.
A mod will come and delete things that are flagged and need deleting.