If you reboot frequently, this is probably not a problem. However if you rarely reboot (this is OS X after all!), or use your computer for crucial work, I would recommend discontinuing use of Yahoo Notify, and rebooting.
I've unfortunately been unable to track down the source of the leak, remaining unsure as to whether it's in my own code, or a problem with the libyahoo2 library.
I sincerely apologize for any problems this may have caused .