As mentioned above, traffic and interaction patterns vary greatly. Some organizations rely heavily on their messaging system, which creates very heavy user interaction. Other organizations may not rely so heavily on the messaging system and therefore have low usage levels. The demand your users place on Microsoft Exchange Server has a direct impact on performance and the number of users that can be hosted on one computer. The same hardware, performing the same functionality, can host 500 light users in one organization, but only 150 heavy users in another organization.