Hi Tonia,
The Cisco Server names including Pub and subs should be no longer than 12 characters, after that it will truncate.
With the Community string itself, this is only limited by the SNMP network packet size as far as I am aware of. I have tested up to 50 characters in Prognosis, would you prefer something longer than this?
For Gateway, the limit is 130 characters after this it does get truncated.
Regards
Jitesh