I'm not saying it has to be PhD-thesis-level, but if proven wrong you are morally obligated to update the information or remove it. Otherwise you are spreading false knowledge. This doesn't apply to opinions ofc (the bulk of private blogging).
Screw entitled users though, they should fix it themselves :)
After 20+ years of working in the business and reading ridiculous amounts of articles, and some books, I can quite easily find clear errors or omissions in most everything written about computers and programming, Knuth excluded. If everyone were obliged to update to fix any errors, even only factual, it's likely that much - or even most - of all I've read would never have been posted for me to read in the first place, and I think both the world and I would be poorer for it.
Correctness is important, but so is the ability make judgments of validity, to critique, disseminate, inspire and express ones thoughts, even when they turn out to be wrong.