How many accounts we put on a server depends on the type of accounts and the specifications of the server and it's network connection.
Rather than setting a specific number of accounts (or websites/domains) per server, we pro-actively monitor the resources of the server (including processor and memory usage, hard drive space available and network bandwidth) to determine how much of a server is being used.
The main reason for this is that not all websites are the same. Different websites have different needs and we do our best to cater for them all. Pro-active monitoring of a server allows us to maximise customer experience and provide stable, quality hosting platforms for all.