These kind of whatsapp groups are only created for promoting scams and scams only. Sooner or later real purpose of group creation is revealed by asking to participate in some HYIP progam.
One post per day limit: nothing more puzzling than this.
Forum like bitcointalk.org are far better and content rich places to get reputed, trusted information and data.
This is very true, I joined a group where they showed pics of some huge transformers and said it was bitfury's container and tried to make people invest in it..