If you think something is spam or egregiously offtopic, you can flag it by going to its page and clicking on the "flag" link. (Not all users will see this; there is a karma threshold.) If you flag something, please don't also comment that you did.
It may be lame, so don't upvote it. But if we start flagging lame articles it kind of defeats the purpose of voting. Save flags for stuff like the political article I submitted yesterday :) that you feel are seriously off-topic.
The last part of that I sometimes ignore: I find it polite to explain why I flagged something because the submitter might not figure why it got trashed :) (and if nothing else that stops a later "Why?" thread).
(and for the record I flagged this too for other reasons)
EDIT: I suspect apu flagged it for being "lame" because it was a self-submission.
I left a comment for the exact reason you describe. However, I flagged it because it was a zero-content post, not because of the self-submission (although obviously that didn't help).
yeh sorry I misphrased: I was thinking the fact it was a self submission too tipped the balance to flag it (it did for me: I was kinda assuming by extension - my bad)
http://ycombinator.com/newsguidelines.html
It may be lame, so don't upvote it. But if we start flagging lame articles it kind of defeats the purpose of voting. Save flags for stuff like the political article I submitted yesterday :) that you feel are seriously off-topic.