I actually found an interesting use case with Twitter a little over a week ago when Pier 29 in San Francisco was caught on fire. I initially heard about it on Twitter from one of my friends. I instantly searched for "Pier 29" and found a plethora of relevant images and links as the story was developing.
Sure, searching Google News or going on the /r/sanfrancisco subreddit might've given similar results, but there was an intense amount of content developing in real-time. I was able to see images of the fire from different angles and perspectives and I felt that this was a strong feature that Twitter has. I personally think that Twitter's business model _relies_ on having a large userbase. Using Facebook would be fine with a small userbase, but Twitter's model is much different.
A similar use case: I noticed the sunlight on the wall of my apartment's courtyard was a bright orange so searched twitter for "Berlin sunset" and right away found a gorgeous image someone had just made 5 minutes ago.
Sure, searching Google News or going on the /r/sanfrancisco subreddit might've given similar results, but there was an intense amount of content developing in real-time. I was able to see images of the fire from different angles and perspectives and I felt that this was a strong feature that Twitter has. I personally think that Twitter's business model _relies_ on having a large userbase. Using Facebook would be fine with a small userbase, but Twitter's model is much different.