YouTube is great for so many reasons - mostly the ability to play any song on demand for free. In light of the all of the free streaming music (Spotify, Mog and Rdio) services out there, Youtube has been doing this for a long time. Create playlists, share music with your friends, watch videos on your iPhone or a device connected to your TV - you can take the free music wherever you want.
I recently found a video for 'How to Live Alone (With the Dogs)' by The Pernice Brothers. Since their collection is hard to find (at least on Amazon and iTunes, I haven't called Laurie's in Lincoln Square yet), you can imagine how excited I was to be able to find it, play it several times and even share it with friends.
After watching the video, I wanted to leave a comment telling the world where I first heard it! But what should have been an easy task wasn't a good experience at all.
When it comes to usability in products, my favorite issue is error prevention and handling. That is, how a good design can prevent errors and provide a clear way to fix them.
After typing my comment and clicking 'Post', I didn't expect to get an error message. And I was really frustrated when the message only read 'Error, try again'. That's it? How would I fix it? I tried again (and again and again) and couldn't leave the comment because I didn't know what to do next. Error messages should describe what action the user must take to fix it. I never got to leave a comment. I went onto other songs, other things. What a waste of time!
Always provide clear, detailed error messages - frustrated users will quickly leave your site or app and discover music someplace else.