Maybe I should have used a different title to make the focus of this post clear. A DSLR is a camera and no you cannot message someone from your DSLR.
Just in case you get a DSLR for Christmas (lucky you) or have one you never figured out how to use except in automatic mode, this cool simulation is for you. Learn how the different settings on a DSLR interact and which settings to use for which conditions.
Or, if you interested in instructional design, you might find this a great example of what is possible in a simulation.