Can it run on apple Mac’'s?
I don’‘t think so, you need SUN’‘s JVM 1.5, which is imho not available for AIX and MacOS. I don’‘t know about other server applications for Mac, there may be available some. But Linux or Windows should be a better choice, a lot of users use it and so you’'ll likely get better support. I did get no reply to my AIX related question.
Clients like Spark are available for Mac anyhow.
What are system requirements?
How many concurrent users do you have? What back end systems do you want to connect? LDAP? Embedded database? 30 users run usually fine with 64 MB RAM, even 100 users are possible with 64 MB RAM.
To reduce the network traffic you should avoid to create rosters or groups, as they will be updated as soon as one goes on- or offline. Some heartbeat traffic will be sent.
If its so great why is it free !
You may pay for a customized Spark client and other nice features like Fastpath.