Outlook.com is a Metro-skinned Hotmail with Skype and Skydrive integration, without any IMAP support. Microsoft introduced it thusly:
“We think that email can do a lot better than webmail,” says Microsoft. “We decided it was time for a change.”
I don’t see how this is significantly different to any webmail client. It lacks any serious attempt at improving the effectiveness of an email client, and it’s harder to use. But it’s got Skype built in, and it uses Segoe. Woo hoo.