I'm very happy that this exists, and it's trivial to use. My own usage, however, represents a torture-test of the extension. because I have over 38,000 answers. It hung at about 12,000 with the message "Quark stalled - reindexing" but it doesn't seem to have gone on again. I left it alone for several hours and nothing happened. Clearly there's an upper bound on what it can do.