I read a few forum posts about the single site cache vs. the whole network here:
These were over a year ago. I think that Super Cache still behaves the same way, but I wanted to check to see if that was the case. Can you now somehow set the cache to only clear the cache on an individual site. I am particularly interested in the "Clear all cache files when a post or page is published or updated." We are using this plugin on a network with almost 3000 sites. I want users to easily clear their own cache and this setting does that for them. But with 9000+ users that means the cache is almost non-existent because the moment that someone publishes a new post or page anywhere on the network it clears the cache for the whole network.
Thanks for your work on this great plugin. We could take a look at trying to program this, but I hate to go outside of the releases. I want to get the new features in the future as they are released! :)