Yesterday I sent out an email announcement about Tuesday's Free ADDClasses.com Teleseminar : Take Control of Your Time. I was amazed at all of the work related automatic vacation responses I received.
Unless your work is specifically related to ADHD it's not a good idea to be signing up for ADHD related email lists at work with your work email address. Your place of employment does have access to your internet activity and your email account. Not only will they be able to find out that you are doing non-work related activities they may also suspect that you have ADHD.
Disclosing that you have ADHD to your employer is very complicated. In many cases the cons out weigh the pros of disclosing ADHD in the workplace and many people choose NOT to disclose that they have ADHD.
It should go with out saying that you should be spending your time at work doing work. However if you are using your work time for personal activities use some common sense! Use a personal email address instead or your work related email address.