I've not heard of "Opserv", although some networks do have an "Operserv". It's a service for IRC Operators to use for various reasons - akills, server/network statistics, freezing nicknames, emptying out channels and myriad other reasons.
The only Google results for Opserv I could find were just references to OperServ.... I guess it's the newest thing to refer to Operserv as "opserv" even though an op is something completely different to an oper
Regards,