Output caching can significantly improve the performance of an EPiServer site. However since EPiServer Visitor Groups were introduced it meant it was difficult to switch output caching on as each page could be unique for each user depending on the visitor groups matched. Also if a user returns to a page it may change depending on their actions on the rest of the site.
EPiServer Visitor Groups are a powerful feature and output caching can have real benefits in the right scenarios so I wanted the best of both worlds. So I've been thinking about a solution that would allow us to switch on output caching but still benefit from the use of visitor groups.