I left my browser open to the bamboo home page for 9 hours, with no other activity on my workstation, and found that my machine's memory usage had increased from 522M to 1.07G. When firefox was closed, all of that memory (within a few megs) was reclaimed. I've attached start and end screenshots, which aren't terribly informative but illustrate my observations.

It's super easy to create memory leaks by creating circular references between javascript and dom elements. Google "memory leak ajax" and "javascript memory leak" and "javascript memory leak circular" and you'll find a plethora of information about it.

Truth be told, most web 2.0 apps leak memory, but not usually as much as this.