Keep the professional and the personal seperate.

"If you want to appear professional and courteous, make yourself available to your online correspondents. Even if your reply is, "Sorry, I'm too busy to help you now," at least your correspondent won't be waiting in vain for your reply."
- Writing Effective E-Mail: Top 10 Tips

Proper e-mail etiquette is essential especially in the professional world. This doesn't just refer to the actual writing of the e-mail but how long it takes you to respond to the e-mail. I find myself sometimes, waiting by the computer waiting for a response from a professor or a classmate on important information that I need to complete an assignment or a paper. I find it hard to believe that most of the people that I know check their email only two times a day. I check my e-mail hourly just in case there is something important that needs a quick response.

-----------------------------------------------------------------------------------------------------------------------------------------

"...the e-mail administrator has the ability to read any and all e-mail messages (and may fire you if you write anything inappropriate)."
-Writing Effective E-mail: Top Ten Tips

Just because you have a username and password combination doesn't mean that your e-mail is safe. There are people out there in the world that have the power to hack into any personal e-mail or website and expose personal and private information. My boyfriend has a work e-mail specifically for professional reasons and a seperate e-mail for personal items. His job has the authority to check his work e-mail at any given time to make sure he is not doing anything illegal or harmful to the company. I would advise anyone who has a work e-mail to keep that for the professional world and another for their personal life.