It might come back but the date is unknown. (It needs to be rewritten).
As replacement you can try the freedb2 search or one of the many other sources.
(outdated, Attachement removed)If you haven't already noticed, the freedb web search isn't working anymore.
Here is an update:
Download the attachement and extract the new freedb.src to %appdata%\Mp3tag\data and overwrite the old one.
Please read here if you have troubles finding the correct folder.
Note: You can also install the latest Development Build to get the update.