I attribute the phenomena to the fact that the users of tripe such as this have a very limited vocabulary and it's their method of connecting words to form a sentence, while their mind races to find an appropriate word or phrase.
Even more puzzling is how such an annoyance becomes so international in scope. I noticed, as jno intimates, the habit becoming invasive perhaps 10 years ago or so, but was unaware that it had become just as 'fashionable' in the U.K. (and elsewhere) until participating in AnswerBank...
Used, primarily, by those under the age of 18 (at least here in the U.S.) it'll be interesting to see if the speech impediment persists when they are into their 40's and 50's... now that's scary!