My mom's company uses Lotus Notes. They used to use the whole Lotus SmartSuite, but they finally upgraded to Offce 97 a few years ago. The company is finally going to upgrade from NT4 to Windows XP. So, while everything else is being upgraded, Notes is remaining the constant.
It would be a major hassle to retrain everyone to use something else, and I can see them switch from Notes to something else eventually, but not for a long time.