DDOS attack against the CCP servers?
CCP screwed up something with the launcher update?
The end result is the same, few people can login to Eve at the moment.
Update #1 - It would seem their is a work around, it certainly worked for me. So go to https://forums.eveonline.com/default.aspx?g=posts&t=238130 and download the launcher update, install it. My desktop shortcut was broken after this but creating a new one to the eve.exe in the correct folder fixed that up nicely. One thing I've noticed, in addition to chat channels disappearing and other settings reverting, is the logoff option is now gone. You have to exit the game and restart it manually every time you want to change between characters. It takes an age to check the client file also, annoying!
Update #2 - On my linux box this update worked better. I installed the updated launcher from the link in Update #1 and that worked fine without me having to screw around with the library settings as I've had to do in the past. Then I launched the game and it appeared, all the settings were still there, it worked fine. Linux buff!
Update #3 - Success! If you leave the launcher open while in game, something I wasn't doing previously, you can switch between characters on the same account without having to login again using the launcher.