The convenience/security trade-off varies user to user, but for something as simple as FB, it might be considered overkill by most.
I would encourage browsers that support isolated profiles, multiple browsers that don't share cookie storage, or using a jailed site-specific browser approach.
In my limited understanding it's the difference between the webkit engine that OS X provides to developers to use, as opposed to Chrome which probably does something different in that regard. Besides site-specific browsers, there are plenty of makeshift OS X tools that implement their own built in browser, and these applications do indeed share cookies with Safari.
The easiest way to test this is with Safari and any of the OS X site-specific browser or http debugging tools.
I believe this isn't always the case. If you're using multiple browsers in OS X all built on Webkit for instance, they share the same cookie store.
Firefox and multiple firefox profiles isolate cookie storage and I also use Fluid on OS X to build site-specific browsers. The paid version offers a feature to isolate cookie storage within each app.
If one were interested in building something like this themselves or getting into the market, where would be a good place to start as far as acquiring hardware, learning about asic systems, and the software behind these systems?
I've been building my own managed firewall and router systems for awhile on commodity hardware, freebsd, and nice nics and would like to look into taking it to the next level and perhaps starting a business in this area.
I would encourage browsers that support isolated profiles, multiple browsers that don't share cookie storage, or using a jailed site-specific browser approach.