'''Colon''' denotes [[point of view]] in ordinary English usage, as in dialogue.  All [[chat]] developers know this.  [[mediawiki]] knows this.  But somehow the [[period]] is going to be overloaded yet again to create [[namespace]]s ?  When the primary use of namespaces is to differentiate a POV, i.e. that of the service, or that of an individual user, or another meta-perspective, from the main namespace?

Colons in URLs certainly tell the browser which protocol it's going to speak. Likewise, the rules of handling content will vary drastically based on which namespace it's in.  There's a natural convergence between the use of colons in URLs and the use of colons in English, which mediawiki respects.  Creole should too.