The kidernet is a pre-internet communications network comprised wholly of children between the ages of 5 and 13. The kidernet functioned by "word-of-mouth" communication. It operated on the principle that kids will talk about anything if given the chance. The kidernet still exists to this day but has largely become irrelevant since the proliferation of the internet.
The kidernet is interesting in that its distribution is dependent on the distribution of its users. If a user wants full access to the kidernet he must seek out an area of high kid density. Another difficulty is that many of these so-called "high density" areas do not exhibit a high kid density 24 hours a day, but follow a cyclic kid density pattern.
The Classroom, the playground, and the arcade are all examples of areas with high kid densities. One can gain access to the full power of the kidernet at any one of those locations.