Since many of us have a fair number of online accts, this post may be of interest, for when you're not here to take charge.
http://unclutterer.com/2011/08/18/including-instructions-for-handling-your-online-identity-in-your-in-case-of-file/
I have not included the entire link, but assume you can find it. I'm not too clear on how to use the URL button.