Facebook founder Mark Zuckerberg may charge $100 for a message to be sent directly to his inbox. The steep fee is part of an experiment announced by the social network late last month. Facebook has limited the number of messages that can be “prioritized” in this manner to one per week. For everyone else, the system works just as before, with messages sent to non-friends routed to “other” folder. The idea, Facebook said, is to try and reduce spam by making it difficult to send mass messages to main inboxes.”]