BTYahoo! mail sidebar advert

I use BTYahoo! email, which has recently made several supposed upgrades that are really just annoying. The worst is the sidebar on the right of the screen that contains an animated advert. This always appears when I go to the mail page and always slows loading massively, as well as hiding part of the screen.

There's an arrow next to it that allows you to hide the ad, which is fine, but every time I open a new mail, delete anything or perform any action at all that results in the screen changing, the ad reappears. Sometimes it even reappears when I don't do anything at all.

Does anyone know if there's a way to permanently disable that sidebar or at least to keep it hidden for the entire session once you've got rid of it the first time?

Thanks

via Bleeping Computer Last 20 Posts http://www.bleepingcomputer.com/forums/t/510528/btyahoo-mail-sidebar-advert/