If a post is so badly spelt, punctuated, or grammatically butchered that I can't read it easily I skip it. There's plenty of content on Web 2.0; I'm certain someone else has come up with the same insight and posted it in a manner that doesn't require a half-hour of forensic copyediting to decypher.
That being said, I usually don't "call" anyone on such posts unless the poster has made a big deal about it, has cranked out a lot of such mutilated posts (to the brink of spamming), or the poster has called out someone else on a similar issue. The rest of the time I just skip it without comment.
I recommend Eats, Shoots, and Leaves if you want a fun but useful guide to proper punctuation... if for no other reason than how the title illustrates that punctuation marks are there for a reason.
-- Steve