In slightly sad news, the English version of Nico Nico is going to be taken down by the end of 2012. However, Nico Nico is going to be reborn as it becomes one with its older Japanese counterpart. Starting October 17th, both sites are going to merge into one, which will allow users from the English Website to use their accounts in the original site. And best of all, Nico Nico's Japanese Website will allow users to see an English interface after the Fusion Dance is performed, along with transferring their translation data from their account.
The only depressing thing about the merge is that you won't be able transfer your comments, tags, and faves from your account, since they are all going to be lost during the fusion process. However, these things won't go away until the end of 2012, so it should give you enough time to re-add your faves and tags to your lists while using the English Website as a reference.
If my predictions are correct, then this might also mean that we will have access to the Japanese stuff as well. I am also curious if the anime and videos from the original English Nico Nico are going to transfer to its older sibling, which will be a great plus. Since they are still a bit vague about the state of the videos from the English Website, we will just have to sit back and wait for the dance to finish.