Both Firefox[1] and Chrome[2] removed it from their stores. I don't know if we should expect an official announcement, but it seems that neither Mozilla nor Google commented on the issue. Many other sources reported it though[3][4][5].
If you are using WOT in either Firefox or Chromium/Chrome you can just remove it without replacing it with anything. Both browsers cover that for you with Google's Safe Browsing[6][7].