Mine's a labor of love and moderation is a 24/7 thing if you want to do it perfect from the get-go. Take a look at the demand for link-building and directory submissions on any marketing forum -- I wouldn't call myself lucky per say, but submissions are un-fucking-real and most of what comes my way is shit. Even look at the quality of Ezine articles and you see a lot of articles that don't make a damn bit of sense, despite their supposed submission standards.
I'm ready for at least 2-3 VA's for quality, while the final say is still going to be on me. I'm looking to build a brand BTW. If you're looking to be the next Ezine or AC I think you'd have an easier time -- I'm just picky about my site and current niche.
I don't know how to stop the spam -- If you don't give out links, it will cut down on most of the spam, but you have to have something attractive to writers, or money to buy the content.
I realize I've babbled a bit here: 1) It's a fucking hard gig. 2) I'm looking to build something to the standard of bukisa.com only better, lol. They aren't anything like the size of the big guns -- but the quality of the articles and reader base are far beyond the big names (your goals may be different/require less moderation).