In short, if you have any DotMac content, migrate it off or update it now.. You won’t be able to update it in the future…
Apple to Discontinue .Mac HomePage and Groups: “Apple today announced that two legacy tools associated with .Mac, HomePage and Groups, will no longer be offered as of July 7, 2009. The two services are not currently offered as part of MobileMe but were still accessible to former .Mac users whose …”
(Via MacRumors.)