I don't know if you've figured it out or not. I also am not sure that I understand what you're clicking on. The only "about me" page I see is if I click on my user name and then there is an "about me" tab. I don't see any "edit my about me info" there. I see a link to click to see how others see my "about me" page. The way that I know to edit signatures is by clicking on the "User CP" link. That is on the far left side of the options right under the thread categories. It is above the actual threads here on Pet Talk. When you click on "User CP" link, there is a list of different options on the left side that allows you to edit different things with regard to your information and signature. When you make changes there, it changes the information on your "about me" page. I hope that makes sense and helps if you didn't figure out how to do it after clearing out your cache.
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