The headers on both the in-product page and the default homepage refer to Firefox "Help" while everything else refers to "Support." The url contains support as well as the two links in the sidebar. The main Mozilla.com site refers to Support, with subcategories for Firefox Support and Thunderbird Support. The community section of mozilla.com also refers to Support. The Help menu, however, links to "Help Contents." Bug 494083 introduces another instance of "Help." It's my gut feeling that consistency is best, no matter which term we use. David has expressed a preference for Help, which I don't necessarily disagree with. I'm not sure if there was any discussion into this issue when the project was started, or if SUMO was simply picked over HMO for the codename. ;) If support is better than help, then we'll want to change the link in the help menu. If help is better than support, then we need to rebrand. Because of all this I'm also ccing someone from marketing and dev, and the people I can remember who were involved when the project was named.
The word from our UX designer is that a mix of different terms would be helpful in SEO and usability, since people might search for either Support or Help. Since I see no downside to that, I'd like to close this bug as works for me.