The exploit causes the Wii to completely freeze up and runs through the typical YouTube .FLV format. A video of the vulnerability's effects on the Wii can be found here and also shows its effects on other platforms including Windows and an Apple Mac.
It's not much of a threat, according to Symantec, with no strong evidence of public exploits for Linux or Mac systems so far. While the code does freeze up a Wii, the chance of any worrying code floating around any time soon is unlikely.
Symantec recommends users update their flash players with the latest Adobe patches here. The Symantec blog can be found here. µ