This style of writing originated in the advertising world--and its use in advertising stems from hypnosis or more specifically, neurolinguistic programming (NLP).

I am a hypnotherapist myself. This type of punctuation would be used to que the sub-conscious mind in an authoritative matter, as a means of eliciting a submissive response and thus allowing one's message to be more fully focused upon, as well as acquiesced to. It is, essentially, the written version of an inductive speech pattern.

It is effective when it is used correctly and annoying when it is not.