I'd like to counter here that I prefer that sites don't assign vim bindings, or at least allow me to disable them. The reason being that I make extensive use of the vimium Chrome plugin (similar to pentadactyl on Firefox), which maps common vim keys to useful browser shortcuts (j/k to scroll, shift-j/k to switch tabs, f to enable a "type to click links" mode, etc). On 99% of the websites I use, I almost never need to touch the mouse, which is a especially appreciated when using a laptop with a nub mouse.
When websites use these common vim keybindings in an attempt to be helpful or "hacker cool", they completely bork my browsing setup until I disable the plugin for that site. My experience after that is usually a mix of awkwardly readjusting to the default browsing setup and reflexively trying to use vimium hotkeys and being surprised when they do something completely different. So, while Google Reader gets much "hacker" praise for its vim hotkeys, they make the site a lot more difficult to use for me -- there, accidentally hitting my "scroll down" button will scroll to the next article and make me lose my place, for example.
To web app developers, I completely understand that vim users that use plugins like vimium are a niche within a niche and not all that important in the grand scheme of things, but we would very much appreciate it if you bury the option to disable vim hotkeys somewhere in your site's settings menu. Very few people may be affected if you don't do this, but to those that are, it's even more frustrating than sites that remap the arrow keys, use touch events on mobile browsers, break "middle click to open in a new tab" functionality for no good reason by using javascript onclick events instead of standard anchor tags, or break pagedown functionality by covering up the top part of the document with a giant floating "like this on twitbook" bar.
I'm not trying to troll, but frankly, I don't understand why people who want to use advanced extensions like Vimium/Pentadactyl opt for Chrome and its crippling extension API.
With Pentadactyl, what you describe just isn't a problem: the extension captures the keys and prevents websites from screwing that up, unless you want to access them, in which case you just press C-z to enable 'Pass Through' mode.
I didn't take your comment as a troll -- I even considered mentioning that problem in my post. The trust and power that Firefox gives towards extension authors is certainly a strong point in its design for "power users" (letting, for example, Firefox adblockers prevent the ads from even being loaded, while Chrome adblockers can only hide the display elements). The thing is, though, no one browser is perfect; Firefox lacks Chrome's process isolation, support for the latest Flash plugin on Linux, I prefer Chrome's visual design and user interface, etc -- the point being that I prefer Chrome/Chromium for certain reasons external to extension capabilities, and I'm not willing to switch back to Firefox just to get my vim hotkeys to work on Google Reader.
I realize it's not fair to expect web app developers to adapt to my (or anyone else's) custom browser configuration, but in this particular case, they're adding vim hotkeys primarily as a convenience to fellow vim users, not as a defining feature of their site. Given that, I think they should be aware that there is a subset of those vim users who are negatively affected by their kindness.
Humorously, Chrome just completely crashed while I was writing this (running on the latest Quantal beta), prompting me to remove a bit I wrote about Chrome being more stable than Firefox due to its process isolation. I have a hunch that the fault lied in the Flash plugin, however, which doesn't seem to be terribly stable on Linux. I've never had a browser-wide crash on Chromium in the past, but not being able to watch certain Youtube videos and missing the convenience of Chrome's PDF plugin prompted me switch to it. Not sure I made the right decision.
I use Chromium over Firefox purely so I can open many tabs without having to scroll the tab bar. I use extensions to bind keys, block content, block scripts, etc. I realise these work better (and some only work) in Firefox. But the scrolling tab bar is a deal breaker.
Vimium dev here. We actually disabled Vimium on Google Reader because we were getting complaints about how it breaks Reader's own keybindings. If you wish, you can re-enable Vimium by going to the options page; once enabled, its keybindings should take priority over the page's own -- please file a bug if that isn't the case. (However, if you pressed a key that doesn't correspond to a Vimium command, it will automatically pass the keystroke down to the page's own key handlers.)
