Windows 7 x64
Broken: Official Release
Worked: It appears to work with an older 2.69.3 build.
Short description of error
If you have a highly subdivided plane used as smoke emitter memory consumption will go up steadily even with a low res smoke domain. Also memory isn't freed when loading a new scene.
Exact steps for others to reproduce the error
The attached .blend file has such a setup, just press Alt+A and check the memory usage. At frame 200 it's at around 3,5 gb on my system, at frame 300 at 5,2 gb and so on.