I use YSM to drive 384 unique visitors to Joe Buck's affiliate program, but no sale.

I only use related keywords, and my keyword list is not too huge.

Anyone know what exactly happen?

First of all you sent way too many clicks before realizing the offer wasn't converting with the keywords you had chosen. I never test an offer/campaign/keyword set with anywhere near that many clicks.

Give yourself a cutoff of how many clicks you're willing to send (you want to base this on what the offer's payout is) and if it doesn't convert within the click number cutoff you drop it and move on. Another option is different keywords, but again, if it isn't converting at least 1-2 times by the time you get up to 50 or so clicks, don't keep sending up to 384 clicks before realizing you're not converting.

That's just pissing money away.

Also, "related keywords" don't get the job done. You need highly targeted "buyers keywords".