Is empty since a week and has no open edits / relationships and is not credited on any tracklist, as far as I know. Why isn't it removed?
Found cases of this too e.g. http://musicbrainz.org/artist/44b1a9f0-63db-47df-9e6b-1e999f995446
@Andrew: I don't know, your artist (had) open edits... I voted on the one remaining, so perhaps it will be removed tomorrow... if not, it's the same issue as above perhaps!
Another case http://forums.musicbrainz.org/viewtopic.php?id=2935
Merging the databases in the last release has made more problems apparent here. Tests have been added, and I believe the problems have now been solved. See commit 0c7a4f3 for the main problem.