I imported my Songkick history to get started here. It imported most things correctly but there are a few noticeable glitches.

1) Some events imported to the wrong venue, when the artist had more than one show that day. Jimmy Kimmel Live! tapings had this issue.

2) Many of my shows imported without ANY bands marked "Seen" and some of the festivals imported with all of them marked. While tedious to scroll through all 1100+ concerts to mark each show no matter what, it would be somewhat easier if regular shows marked all artists and Festivals didn't mark any automatically, as other users have suggested.

3) A possible solution to the above would be to allow users to import their history from setlist.fm instead of songkick. That site already allows users to indicate ONLY the bands they saw, though it might be tricky for Concert Archives to automatically group multiple bands into a single concert.

Thanks for this site. Feel free to contact me directly if you are looking for admin help. I've got vast experience with songkick, last.fm, swarm & foursquare, setlist.fm, etc. I'd be happy to occasionally help merge duplicates and stuff.

Oh, and on that note, I wasn't able to find a "report issue" button on any page so far to mark duplicates. I've fixed some individual venue names and things but that won't prevent the same errors from being imported again later.