0 clicks, 1 sign up
 

I've posted few days ago my stats here, 22 clicks converted into 3 signups. Yesterday I've converted 0 clicks into one signup. I just don't know, how is it possible. If I only knew the source of this traffic.

Not sure what system this is happening on for you, but I can tell you why this would happen on FNP or PSB.

If you send a surfer to the join form on the 1st of the month, your stats will show a click through from that surfer on the 1st. Lets assume the surfer didn't make a purchase, but bookmarks the join form for another time (when they have their CC handy).

On the 3rd of the month the surfer comes back to the bookmarked join form (which has your referrer id) and joins. There you have it. 1 sale, 0 clicks. :-)