As part of a status alert on Xbox.com, the Xbox Live status has been amended to state the following:
“Users may receive potential fishing [sic] attempts via title specific messaging while playing Modern Warfare 2.
We are aware of the problem and are working to resolve the issue. We apologise for any inconvenience this may cause and thank you for your patience.”
According to reports, all other functions of the Xbox Live and online services are currently working as normal. If you do notice anything strange, please be sure to inform Microsoft immediately.