Clearly some of the comments here lack creativity
This hologram thing is so awesome. I remember a movie called "Paycheck" check it out.
Here are some applications for this hologram tech
1. Porn - enough said. This is like a porn on steroids.
2. Immersive map experience. This is Google street view on steroids.
3. The Iron man experience. Now you can touch your word documents, throw them at a trash bin to delete and onto a printer to print. Its a new UI experience unlike anything.
4. Entertainment. Imagine watching a concert almost anywhere where the artist is in front of you. Its like U2 is having a US tour but you can't go see it because its too expensive. But with this, viola. Bono is in your living room.
5. Military applications could be many. Imagine training soldiers to get familiarized to an environment thousands of miles away.
6. Video conferencing - not that face to face meetings will be obsolete but what if there was an epidemic and travel is not an option but you have to meet a client on the side of the globe? This is certainly a new experience.
7. Health applications. A doctor can remotely do emergency procedures but aiding and instructing somebody.
8. Construction and Architecture is given.
9. Gaming - you've seen that with the Minecraft demo.
10. Property - Now you can visit a house or apartment without going there.
Windows 8 was so bad that Microsoft gave us Holograms to make up for it.
I don't think no one expected this specially Microsoft since most people know Microsoft as not cool. Well Microsoft is still the alpha male dragon and it just woke up and took a dump at Google's and Apple's front door.