HTTP Status Codes:

__0 = 506
200 = 9387
301 = 9
302 = 7
400 = 3
401 = 5
402 = 1
403 = 43
404 = 286
408 = 2
410 = 2
500 = 28
501 = 1
502 = 2
503 = 25
504 = 3
595 = 1
999 = 5

As you can see. 506 of them just no longer exists in any form. 286 go to a page which doesn't exist.

There are a bunch of other varying issues.

Of the 200s, a good number are just domain resell pages. The one for Bruce Willis being a good example. I have the data to have a good stab at detecting them, but have yet to pull that report together.

Some homepages seem to be dubious. e.g. Check the one for Martin Scorsese.

@Travis, want a list TMDB IDs of dead ones for removal? Bit unfriendly to get people to do them by hand.