Rest day and Mapminder

A rest day today, as I prepare for Sunday's half-marathon, so I swam 1.25 km.
Lured by an advertisement on the Runners World website, I looked at Mapminder which was offered on a thirty-day trial. It sounded just the thing, far more accurate than my piece of string or thing with a wheel I run over the map, which I'm sure give me odd readings.
But the technical requirements say, "to run Mapminder you need a Windows-based PC running Internet Explorer 5 or above". Really! If it runs in a browser, why not any browser on any platform? Or are their designers too lazy and ignorant to write proper HTML and Java? And, my dear, surely nobody still uses IE?
I shall therefore wait for a GPS-based system. I like the look of the Forerunner 301