Not just publications - everything. I have a few modern bigraphies and the like, and I really have trouble reading them; most look like they have been written by a 10-year-old. As for websites, well... There is hardly a website I check that doesn't have appalling grammar or spelling, and that includes "legitimate" news sites like BBC, CNN, and most of our local TV and newspaper sites.
It has to be the result of educational standards declining - partially - but a lot of it just comes down to laziness, and a lack of pride. With all the technology available, it has never been easier to spellcheck, so why are there so many mistakes?