This question does seem to have a clear answer in the Filesystem Hierarchy Standard, which specifies
/srv as "contain[ing] site-specific data which is served by this system
This main purpose of specifying this is so that users may find the location of the data files for particular
service, and so that services which require a single tree for readonly data, writable data and scripts
Note: 'Served by the system' doesn't necessarily refer to the Internet. It needn't even mean a network. It's applicable to even a shared system. Further, the words site and service should be understood in their pre-internet meanings. Your site can be "the physics department" or "the finances office".
It goes on to say:
On large systems it can be useful to structure /srv by administrative context, such as
/srv/physics/www, /srv/compsci/cvs, etc. This setup will differ from host to host. Therefore, no program
should rely on a specific subdirectory structure of /srv existing or data necessarily being stored in /srv.
However /srv should always exist on FHS compliant systems and should be used as the default location for
You should therefore further structure your date in directories such as
/srv/backup and so on.
I should also mention that few people do this anymore. But there is no good reason why they don't. The standard is by no means out of date.
/var is traditionally used for things like print-spools and log-files, but it's also used by the apache web server (on debian systems anyway - SuSE use /srv); There doesn't seem to be consensus on whether
/var is a proper directory for shared data. But if you decide to use it instead, you will have no regrets I'm sure.
Note also: Karthick's answer is by no means wrong. The FHS says /srv " should be used as the default location for
such data", but the standard leaves some room for your own preference, depending on how you interpret the terms.