With the widespread use of the internet, more and more children get acquainted with its various uses at a young age while an increasing number of teachers are designing learning activities that utilize various internet services. Toward this direction, teachers need practical examples of pedagogically verified learning activities. This paper presents an experimental case study of a learning activity meant for teaching preschoolers geometric concepts, which uses communication tools from the internet. The activity constitutes a developmentally appropriate adaptation of a successful model, known as "Monster Exchange'', to kindergarten. The paper presents the proposed adaptation, the experimental findings regarding the errors children mad, the difficulties they encountered, and finally, the drawings that children produced, with the aim of evaluating the appropriateness and the learning value of the activity.