Got a few questions.

1) How long do buyer/seller have to leave feedback after the auction was won?

2) Is there anything that protects from retaliatory feedback? For example, some sites won't make feedback known until both sides left it or until one of the parties let their right to leave feedback expire.

3) Where can I learn more about how feedback on Flippa works? Thanks.

1) 30 days I believe
2) Feedback appears right away. You can speak to Flippa support if you feel it wasn't justified
3) Don't know - check the Flippa site. It's a simple process though.