I always knew Sitecore provided Dictionary support for a long time but I also knew there were, shall we say, scalability problems. Like, let's say, general user access (it was located under the system node) and the inability to create individual dictionaries for individual sites. Because of that, I, and apparently others, have been inanely custom rolling dictionaries. That is, until I came upon Scott Mulligan's article highlighting the latest changes in Sitecore 6.6 (yesss, it's been a while, I know [sighs, rolls eyes]) that convinced me to finally stop reinventing the wheel and adopt the Sitecore provided solution.
There are resources out there to help get started like John Wests' seemingly canonical post. There's also a super handy article by "sitecorecode" (I couldn't find the author's actual name but I guess you know who you are). And my long time friend M3, as he's known colloquially, breaks it down like a legend.
Friends, romans, countrymen... et al, the Setting Up a Sitecore Extranet article I wrote in 2011 is one of my most trafficked. It occurred that many of you could benefit from the additional changes that I've made since then, so that those who are setting up your own system by hand could now benefit from a module that manages most of the process for you. For visual reference, I've made a video for a quick intro to the module.
There already exists an extranet module on the Sitecore Marketplace but I'm not the developer of it. Sitecore is. The documentation says it was created in 2007 for Sitecore 5.3. I've never used it so I can't speak to its efficacy. I'm presenting my own solution and you're free to choose which will work best for you.
I recently had a request to detect the browser language for a multilingual site I support. Now this certainly isn't anything new and here's the canonical/obligatory John West post written about it. I'm not trying to rewrite what he's done. My solution is different and deals with different needs. The requirements I had were:
*set the context language to the browser language if the site has item versions in that language
*if the user changes the language through a dropdown selector maintain the new language settings