Don't use your work email for Tribute A Gift, unless you are the boss.
Employer's have the right to monitor your email traffic. We don't want to see anyone get in trouble because of us. Besides, if you're on the clock shouldn't you be doing your best?
Put yourself at the end of the pending downsize list by doing a great job for your employer. And you'll see good things coming your way. Save your personal business for your personal time right?
Now if you're self-employed, or paid for performance, or the top dog at your shop, then it doesn't matter what you do with your computer.