If you're using a forum, outré in front of a computer. Keeping track of things is one of the things computers are _best_ at. Get yourself a password manager. I use 1Password, but I hear good things about KeyPass and LastPass too.
Seriously - you can't manage 2013 grade password complexity requirements for all the places you need passwords in your head any more (it's likely you never could…)
Get a tool to help, computers are wonderful tools.
I've got KeePass, but I haven't used it remotely as long as I've used many websites. Also, I don't have my KeePass DB in Dropbox, so I can't access it from other computers.
More than that, I'd rather not put my KeePass DB on someone else's machine in the first place. But I'll easily trust strange computers with a password for some crappy forum.
There's always something you risk compromising. I prefer some forum account to be compromised.
Seriously - you can't manage 2013 grade password complexity requirements for all the places you need passwords in your head any more (it's likely you never could…)
Get a tool to help, computers are wonderful tools.