Personally, I don't see any upsides to using flash breadcrumbs (the Community > Feedback links at the top), but I certainly see a lot of downsides:

• Doesn't work on iPhone/iPod Touch/iPad.
• Slow.
• Breaks frequently (as happened recently when they stopped functioning entirely).
• They're in the wrong order (lulwut)

PHPBB already provides a HTML breadcrumb system: why overcomplicate things and try to use Flash when it clearly isn't working?