I'm in a bit of a quandary. I like to prerelease chapters and snippets. This is both to boost the eventual sales of the book and get feedback (not so much from this blog, but there are some writer's sites that have been exceedingly helpful).
I'd also like to submit things for publication. So what counts? At least one Sci-fi magazine says anything, anywhere, anytime is pre-publication and therefore cause for rejection. It's not so bad for self-publishing, but I'd hate to "Sc**w the Pooch" to borrow a military aphorism for other modes.
On the other hand having snippets lodged in the bowels of Google with a definite time-stamp that I can't possibly alter does protect me from charges of plagiarism.