My grandmother is 90 and using a computer. I am happy to have set her up with one a couple of years ago, against the recommendations of other family members who thought it would be no good.
It is a standard Windows XP computer. She emails, surfs, writes letters and does online banking.
What is stopping your senior lady - eyesight can't be fixed with glasses anymore?
I admit I keep wondering if I should show my grandmother more interesting things, like social stuff. I am just not sure what - World of Warcraft maybe? I myself don't chat on the internet (except HN and Twitter), so I am not sure what would be a good place to send her to. Maybe just Facebook? (I also don't use Facebook, but maybe other family members do).
What would be a good site for multiplayer games? I myself use Brettspielwelt, but the user interface is not very good.