How effective are one time offers?

How effective are one time offers on a thank you page or download page after a visitor has purchased a product or subscribed to something. I've recently added a secondary offer on the thank you page after a visitor has joined my list. I was wondering what experience other people have had with one time offers. Also has anyone got any tips to make them more effective? Any information would be much appreciated.

Thanks
Peter

 

I'd say these are effective to give people a positive feeling about your site.

 

I'd say these smell infomercials.

 

They are very effective.. I use them on all of my opt-in lists and I have a OTO write after my "confirm" page.

It's the quickest way to pay off the PPC adspend.

 

Speaking for myself personally, I hate them, I get the feeling that all I did was subscribe to someone who is trying to sell me something. If I have bought something, I am even more annoyed because I just purchased something and you are already selling me something. I say wait a while than send another other. JMO

 

It depends on the person. Some people who just get annoyed (I myself would) or feel pressured to sign up because they might pass a great opportunity if they do not (the reason why most people use this method in the first place).