Opt-in form embed inside comment is not showing up

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I was following the Multiple_Hit_Strategy_for_Rapid_List_Building guide to setup my wordpress blog. However, I couldn't get the opt-in form to embed inside the comment working. The pdf says to enter 1 & 2 for subscription alert but the illustration uses the 3rd comment. I tested commenting myself but I just don't see the embed opt-in show up.