run-on sentence = 373,000 hits
misplaced modifier = 40,100 hits
I don't believe in run-on sentences. My working theory is that they're bogeymen invented by professional writers in order to scare the crap out of aspiring writers, divert newbies' attention from more important issues like misplaced modifiers, and thereby thin out the competition.
In all my years of copy editing and reading friends' never-to-be-published novels and memoirs, I've never seen a sentence like: Joe heard footsteps they crunched on the leaves his breathing quickened he broke into a run it was too late the hot breath was on his neck. (Of course, I've never edited Cormac McCarthy, but that's another discussion.)
Nope, the run-on sentence, in my experience, is not a real problem for writers. However, I do frequently come across misplaced and poorly placed modifiers: Wilson took a three-year hiatus in 1994.
The Google search affirms my suspicion: run-on sentences are overhyped.
Causes June Casagrande Supports
Planned Parenthood, ClimateCrisis.net, the Richard Dawkins Foundation, Pet Orphans of Southern California, KIVA