I wrote a post last week about Rebecca Thistlewaite and the big bad meat company. Apparently she's had second thoughts about publishing it. You'll find a google cache of her original post here.
This is actually a problem when you look at blog archives. Most blogging software allows the author to go back and retroactively change what they wrote, and there's no easy way for the public to know that.
This is different than posting an update; I've had the experience of having someone completely rewrite what they wrote and then claim that it's the original.
As always, measure your blog by your own experience, and take any blog and any claim on the blog, with a grain of salt. Not everything written is accurate or true, and some folks won't stand behind what they've written, even if they appear to invite discussion.
21 hours ago