Update 2/26/2013: In response to your feedback, we have also raised the limit for Office 365 for Education plans (A2, A3, A4) to 10,000 recipients per day.
In response to feedback from our customers, we have increased the recipient rate limit within Office 365 Enterprise (E1, E2, E3, E4, K1, and K2), Professionals and Small Businesses (P1), and Government plans (G1, G2, G3, and G4) to allow users to send email to up to 10,000 recipients per day. These new limits also apply to standalone Exchange Online plans (Kiosk, Plan 1, and Plan 2). Previously, the recipient rate limit for users of these plans had been set at a maximum of 1,500 recipients per day.
Recipient rate limits exist to discourage users from sending large volumes of unsolicited commercial email, commonly referred to as spam. These limits protect our online service from becoming a source of spam and, as a result of these protections, keep our customers’ email messages flowing. Datacenter enhancements have allowed us to increase this limit while maintaining the same level of protection.
These limits apply both to email messages sent within an organization and those delivered to external organizations. The best way to avoid exceeding the recipient rate limit is to use distribution groups when sending messages to large numbers of recipients. Distribution groups stored in the shared address book are counted as a single recipient toward the recipient rate limit. For more information, see Strategies to Support Bulk Email. Office 365 customers who need to send legitimate bulk commercial email — such as customer newsletters – should continue to use third-party providers that specialize in these services.
If you would like more information on recipient rate limits, see Bulk Email and Daily Recipient Rate Limits. We made this change because of your feedback. Thank you for sharing your thoughts with us, and please keep it up!