In the early days of Flash, the security sandbox was quite lax and sandbox security errors were almost unheard of. With each new version, however, Adobe (ok, ok, Macromedia) heightened the security of the player to address XSS (cross-site scripting) issues and other security concerns (like the hijacking of trusted network data from untrusted networks).

It looks like spammers are finally catching on to the whole Web 2.0 thing. I just received an email that tells me that we're about to enter the era of Spam 2.0. Notice the rounded corners, the fancy reflections and the pastel colour palette. (Yes, I'm now officially in no man's land with my spelling now -- having lived in the UK long enough to pick up the spelling of certain words and yet not others!)
Oh yes, Yahoo! So go check it out. And they even have a link to OSFlash on the page in the External Resources section. How cool!
I've got my ISP looking into it now and I'll post an update when the issue is fixed.