Does Yahoo Mail have a memory leak?

I'm not sure exactly what's going on, but I'm having a horrible time trying to use Yahoo's web-based email with Firefox this last 36 hours or so. There is some kind of really bad memory leak in the system that makes Firefox's memory use jump up to over 300MB as soon as I look at just two or three files. I've even disabled all my Firefox plugins, but to no avail; their webmail client is of no use to me right now, and I'm getting tired of running Force Quit on Firefox every time I try to use Yahoo Mail.

I'm not sure what the problem is, but their webmail client runs better on Safari, even though it can still get painfully slow. For now all my Yahoo email is going through my iPhone.

As a cool note, I can easily see the mail client in Firefox go nuts because I have a program installed on my Mac menubar named MemoryCell that shows the memory use of the currently-running application.

Now, back to the email: Dear Yahoo -- please fix this problem soon! I kind of enjoy reading and writing my email!

Has anyone noticed that "software as a service" (SaaS) is taking a real beating lately?