I used the email lists export (thank you Able for having that feature) to migrate my subscribed users to my list server. The problem was the list server requires quote delimiters and the AC7 file doesn't have them.
I thought Excel could do it by opening and resaving the CSV file. No-go, it's a common problem in Excel 2007 apparently.
Microsoft wrote a nice little VBA.Excel app to do it for you. Here's the link with instructions and the code.