It should also be mentioned that discussion forums like this and stack overflow are useful to search-engines in determining search position. So making sure discussions of these packages always have links to the correct documentation pages will help search engines point to the best result.
On this, I was thinking about developing support on community.rstudio.com to "own" an r-package tag, so (in addition to the "watch" options you now have with tags) package creators, maintainers and others interested can stay on top of discussions related to it. (For example, we really should be pointing most Bioconductor and rOpenSci package questions to their respective -- and excellent -- support forums)
If we did that, it would make sense to have tag/package landing pages here, which point to the author's preferred documentation website.
But Other than a list of desirables (tag ownership, better monitoring options, tag landing page header text), I haven't started on this yet.