Students: Eastern now expects you to check your student email account on a regular basis. Your professors, advisers and all other university employees are going to communicate with you via your student account. This means you can't use your Gmail, Yahoo or other email accounts for university communication anymore.
Faculty and staff: Eastern requires you to communicate with your students, co-workers and outside agencies or people through your university email account. You can still use another personal email account for personal emails, but university communication must be through university email accounts. Eastern expects you to check your university email on a regular basis. You can expect your students to check their email regularly, meaning improved communication with them.
Some fine print: You should be aware that emails sent via university accounts may be considered public records and may be subject to disclosure under state or federal law.