There seems to be a problem with links to user profiles from the Home or Webteases pages. If you click on someone's name it says that they do not exist, when they actually do.
I compared the bad links to working links in the Forum:
I noticed this as well, it's been going on for at least a couple of weeks now. Not sure what would have brought it on, but you can work around it by deleting the text "amp;" from the URL. Hopefully it'll be fixed soon; it's not too terrible, but does get to be a bit of a hassle having to take the extra step to get to a profile page.