Daily build in software is taking the source code, compiling it and generating the executables, then running that nightly. This is considered a best practice since it catches errors that prevent the build sooner rather than later, which makes it easier to fix. And if the build works, then others can make sure they aren't introducing errors.
What would be the equivalent for a schematic design? Clearly I can't build the PCB, but there might be something more than generating the netlist.
Edit 1/21/11: Also a smoke test is running some tests against the build. Again, not possible. I like the DRC (design rule check) idea, I'm thinking of checks such as that.
Edit 1/24/11: I was think of the schematic since that's what I do, rather than the PCB.