I stumbled across a copy of Benjamin Franklin's "Poor Richard's Almanack" complete with woodcuts, funky spelling, and antique typeface.
Two things occurred to me:
1) American society was founded at the same cultural moment that produced the "Witlings"... that the same strands of thought and influences that shaped Frances Burney's play were the "modo proprio" of the time of the founding of our country. There is so much in Dr. Franklin's little volume that seems to be EXACT quotes from the play (of course, Franklin was read in England as a "Savant" as early as 1743 and probably would have been picked up by Frances-- will be interesting to look for an explicit connection.)
2) The Almanac as a literary form strikes me as a witty person's cliff-notes... providing the material to drop in conversation without ever having to have been exposed to the primary sources. A new almanac would be published every year with new tid-bits, thus amplifying the idea that certain thoughts were indeed "in fashion." Imagine taking your ideas (or someone elses for that matter, wearing them and calling them your own) down the runway to strut and be seen in full view.
Seems like ripe ground and quick access to a cultural phenomenon of that time.