The full URLs for each theme answer were:
PETA.ORG
SENATE.GOV
BROWN.EDU
PINTEREST.COM
NAVY.MIL
Each of those answers could be anagrammed to another answer in the grid- but you had to remove one letter.
So, PETAORG anagrams to PARGET by removing the O. SENATE.GOV anagrams to STONE AGE by removing the V. BROWN.EDU anagrams to RUB DOWN by removing the E. PINTEREST.COM anagrams to CONTRETEMPTS by removing the I. And, finally, NAVY.MIL anagrams to VAINLY by removing the M.
If you order these from top to bottom & left to right in the grid, you spell out MOVIE with the letters that you had to remove in order to complete the anagrams.