Abstruse vs. Obtuse

Some writers seem to be confusing obtuse with the word abstruse, as in these incorrect examples on the web:
Believe it or not, the American public wasn't always in love with Alfred Hitchcock. Because his movies were often too intelligent or obtuse, he had more fans in the film elite than he did in the general public.
Grizz tends to make Shakespeare-esque, outsider-looking-in type observations about the situations at hand, while Dot Com spouts highly intelligent, yet obtuse references that send you (or maybe just me) to Google.
Having finally struggled through Ulysses, and yes it was a struggle, I had no patience at all for FINNEGANS WAKE, which is even more obtuse. Has anyone actually read it? All of it?
I chide Brad DeLong all the time for making excuses for Greenspan’s thick, obtuse, obscurant speech.
In each of these examples, the context calls for a word that means "difficult to understand." That word is abstruse:
The mistake of using abstruse where obtuse is intended seems to be less common, but it happens:
It is really abstruse to find Avatar not grabbing anything from the Oscars. It was altogether a new theme with a lot of innovations
This movie fan seems to be reaching for obtuse, a word that means "lacking in perception, stupid."
Bottom line: Barely comprehensible language is abstruse. Stupid people are obtuse.
Note: Obtuse derives from Latin obtusus, "blunted, dull." An obtuse angle is "blunt," as opposed to being "sharp."

From: Daily Writing Tips