After a single field sign-up (email address only) for the newsletter of one of the biggest online department stores the Netherlands, I saw something very interesting. Expecting to see a two part sign-up process (asking additional questions) they asked me to add another emailaddress.
Secondary email address
A captivating thought: Add a secondary address, in case the first one bounces or becomes otherwise invalid, the sender could switch over to the secondary address and still retain the communication with that customer.
In this case you could only go and do another (different) sign-up. How many sign-ups do you need? I wonder if this really adds something to the whole experience and if they have any additional sign-ups (they would have otherwise lost) via that link. But would I always advise to do something with the “thank you” page and turn that attention into value. may it be by asking extra profile questions, showing the latest promotion, giving attention to other (maybe even social) channels… What would you have put on that page?