When I started using Vim for my day job -- beyond server config editing and quick text file notes -- one thing I struggled with was the project management side of things. Visualising projects and quickly navigating files seemed more painful than some of the IDEs that I'd grown used to, so I was constantly trying different project management plugins in Vim.
If you work on several projects at any one time, then it can be nice to have project-specific settings. This might be something as simple as different code formatting styles, but it could be more complex build system configuration as well.
In Project Specific Settings with Vim, Adrien Giboire writes about using
.exrc files. You have to
set exrc to make this work, and it comes with caveats -- if someone commits an
.exrc with malicious commands then you could be in trouble. Adrien explains all of this and also how he uses it with real projects.