When your tech-clueless relatives ask you how to send a digital photo to friends, you can walk them through signing up for an account on a major photo site such as Yahoo Photos or Webshots, or you can talk them through attaching a photo to an e-mail--or you can send them to the simplest photo site in the whole world, Picupine.
Picupine lets you upload a few pictures, give them titles, and then it sends you a private link to a slide show that you can then forward to anyone.
It's really easy. It's also really limited: The pictures expire in one week, which has its advantages but might be upsetting to a person who bookmarks an album only to see it later evaporate. And there's apparently a maximum upload size, which I ran into during testing: the upload process terminated with an error after chugging along for two minutes, and it erased my list of files. Speaking of the list of files, there's no upload application, and you can't multiselect from the upload window on the Web page, so adding pictures is a pain in the neck.
Picupine is simple, but it's not robust. I miss the old BubbleShare, which used to be a rich site with a no-sign-up photo-sharing system. Now it requires a sign-up, but you do get cool features. I think the trade-off was worth it.