What does a CE mark have to do with software?

That's what we thought when we were first asked whether StepByStep was CE registered.
Early in 2014, the MHRA updated their guidelines for defining software as a medical device.
In summary, it defined that Software intended for use for by patients in the UK to diagnose or treat a physical or medical ailment (condition or disease) must have a CE mark. This was done in recognition of the proliferation of 'apps' becoming available with no evidence base regarding their effectiveness.
It also turned out that it was illegal in the UK to do research with Clients using software that was not CE marked.
So we went through the process of gaining CE registration for StepByStep. As StepByStep has a strong existing research base, this was a lengthy, but achievable process (see here).
So now you know.