We now have a number of high-rep users who can review close flags - there is no need to flag posts for moderator attention if you feel the post should be closed.
Please reserve "flag for moderator attention" for exceptions like spam and other bad behavior which warrant immediate attention.
If close flags are not available (you have less than 3,000 reputation) please use "it doesn't belong here, or it is a duplicate" for questions which should be closed (unless the question or answer you are flagging meets another flagging criteria).