MP3 Tag Studio doesn't support any online DB as far as I know. Not in the versions I've used. It does fast tag to file and file to tag parsing though. As well as batch processing for all sorts of stuff.

Does TR allow you to group a set of files by anything other than folder structure or manual selection? For instance, can you sort by tags within one of its views (like you can do in emplode)? I'll give it a try soon.

CDDB requires licensing fees and their licensing agreement is not very flexible (they're selling the work of the public that built their DB). FreeDB seems to be doing great and has picked up tremendous popularity.

Bruno