TYWKIWDBI, a blog of Things You Wouldn't Know If We Didn't Blog Intermittently, that recently discovered the Oxford University Press blog, and found an essay on the history of the filler-word "like." (Not necessarily the Facebook-style usage, but more like, um, like this.) Full-time UST MBA students learned about ways to eliminate this filler word and others during Launch Week. Here's some background from these additional blogs:
I had assumed [like] was a recent innovation. It is not.
The ubiquitous modern parasite like can perhaps be traced to early usage, but the causes of its unhealthy popularity in today’s American English remain a mystery...Of some interest is the fact that the adverb belike once existed and may still exist, at least in dialects. Consider the following: “All these three, belike, went together” (1741; OED). Take away be-, and you will get a charming modern sentence: “All these three, like, went together.” Belike meant “in all likelihood.”
My hypothesis is that at a certain moment like freed itself from the verb to be and became an independent filler. It has been used in British dialects as it is used in American English for quite some time and was probably brought to the New World, where it stayed “underground” until approximately forty or fifty years ago...
It need not even be called an adverb, for it is a parenthetical word and should be flanked by commas (as is done in most modern editions that contain samples of such usage). But the part of speech called adverb has always served as a trashcan for grammatical misfits...