Multiple Google Chrome installations?

Every time I update Google Chrome, it's installation folder keeps getting bigger and bigger (currently 0.99GB) because older versions are left uninstalled if I understand correctly.

I would like to know if these older versions are really necessary for the current version to work? Can I simply delete them?

If you have no idea what I'm talking about, maybe this will help:

http://img827.imageshack.us/img827/3856/鈥?/a>Multiple Google Chrome installations?
Just delete the old folders.There does not seem to be any negative impact on the browser or system.

d3100