I recently had to do an Erase and Install on my Mac. Now when I go into iWeb, even after logging in, none of my sites appear. How do I get them back into iWeb?
Unfortunately you are at the mercy of crappy application design by apple. The websites themselves are saved in a file here and you need it for the websites to appear in iWeb.
If you do not have a backup of this file then I think you are screwed and have to basically redo the website. Never had .mac so maybe it works better with their service.
Of course if you have a backup of your computer then you can locate that file and just put it in its place and it should work.
Have you setup .mac to sync again? My guess is once you re enable iweb syncing, it will put the websites back. It does concern me though if you reformatted only using .mac as the backup.