Groups will also be discontinued on July 7 when Apple shuts down all group email address, group HomePages, message boards and iDisk "Groups" folders. Your data will be safe, however, as Apple will move the "Groups" folder to a new folder on your iDisk called "Groups Archive."
While I never used Groups, it's kind of sad to see HomePage go. I can remember building homepages on my old 333mhz G3 iMac. It was so easy to make a quick-and-dirty site for sharing photos, etc. with grandma. No, it wasn't the cleanest code ever produced, but it was fun back in the day.
Of course, Apple recommends that customers consider MobileMe Galleries and iWeb as an alternative. You can get the full run-down here.