A note was sent to MobileMe members today stating that as of November 8th, Web pages published using the obsolete .Mac service will become unavailable. Those publishing via iWeb will not be affected.
If you're one of those still going about things this way, fret not. Your content will not be deleted. Instead, you'll find your content stored on iDisk and, should you wish, you can republished your content through MobileMe tools, like Gallery.
Apple first warned of shutting down its legacy .Mac services over a year ago. A FAQ page pertaining to this can be found on Apple's support forums here.
It's certainly the end of an era, but bigger and better things have arrived. Mark your calenders for November 8th and take a minute to remember just how far things have come.