people joining mylot after seeing your discussion

I think someone can only be a referral by signing up from your link. The link in the search engine results is not your link so you could not be that person's referrer. If the new member liked your discussion they may want to add you as a friend, and if they want to respond to more of your discussions, then you will benefit from their activities.

Good question. I don't know the answer but will be following this discussion to see what happens. I honestly can say that when I do a search I haven't seen mylot come up in the results.