Is anyone having trouble logging out? (Not a rhetorical question - want to know how many people can't.) If so, simply clear your PokeBeach.com cookies and it'll let you do it again.
For Chrome, hit the wrench in the top right corner, select "Tools", and then "Clear Browsing Data". Check off what you want to clear and logging off will work.
A cookie, also known as a web cookie, browser cookie, and HTTP cookie, is a piece of text stored on a user's computer by their web browser. A cookie can be used for authentication, storing site preferences, shopping cart contents, the identifier for a server-based session, or anything else that can be accomplished through storing text data.