Of course this defines the reason to short YHOO. Because the company doesn't appear to give a damn about its product and its user's experience. It's a frustrating shame because the layout of their financial info can actually be useful.
Until the company cleans up the spam everywhere (in every message board or conversation discussion or chat room or whatever), that service will be impaired. As much as I am annoyed by the spammers, the fault and responsibility for them is the idiots at YHOO.