There are no limits to how many email messages you may receive; however, there are limits to how many messages you may send.
The maximum number of recipients in the To:, Cc:, and Bcc: fields in a single email is 500. You can email 10,000 recipients in a 24-hour period. After the limit is reached, you will not be able to send messages until your total sent messages drops below 10,000. This is a rolling limit meaning if you email 10,000 people at 10 a.m. on Monday, you will not be able to email anyone again until 10 a.m. on Tuesday.
You can find more information on Microsoft TechNet.