I have 8 and am introducing them k-4. I have used them in first grade and are presently spreading the word in other grades. I have found most apps for k and 1- I am about to blog about our first experiences and look forward to hearing…"
I'm not sure the "competitive element" of how many join would strike a chord with our teachers.
I still like the picture idea- it fits with what we are doing here. Perhaps we should think of a theme?