This is a sweeping generalization at best and wrong in most cases. It is perfectly possible to publish in a 'gold' open acess journal like the ones owned by PLoS, in which case your information is published under, for instance, some CC license. Even most 'traditional' journals nowadays allow self-archiving preprint and/or postprints in an institutional repository like Harvard's or in ArXiv ('green' open access).

Not necessarily true, for the reasons outlined above.

The same goes for Slashdot, Wikipedia, the local philately club and most communities I can think of. More seriously, it also happens that a paper is vastly improved thanks to constructive and insightful comments by genuinely concerned reviewers.

I can sort of see what you mean by this, although most journals allow authors to post supplementary information (or just add a link to one's web page). Is this really such a problem in practice?

There is a reason why jargon exists: it helps specialists communicate. The reason is not to exclude non-specialists, which may be an unfortunate side-effect from time to time. There are other media for that purpose (communicating the results of important research to a wider audience).

Oops, thanks for the correction!

Good point. IMO exluding self-citations is good practice for pretty much all citation-based indicators.

The summary is pretty inaccurate. The h-index was proposed by Jorge Hirsch, not Jorge Hurst. Rather than give a vague description, why not simply provide an exact definition? The h-index of a scientist is the largest number h, such that he/she has at least h papers each of which have received h or more papers.This is easier to understand if you look at the picture in the Wikipedia entry for h-index.