Until February/March of this year I think, I didn't use Twitter nor believe in why I would but I then decided to give it a fair try.
Why Tweets have value?
At first, 140 characters may seem too little space to express any single idea, but after using Twitter for a few months I came to realize I really don't need that much more space to express any single thought. Think of it as an elevator pitch. If I can't grab someone's attention in the first 140 characters what makes me think I can in 4 paragraphs?
Twitter in my opinion makes you a better writer and teaches you to express your ideas in the most efficient way possible.
When I scan my feed on my phone or at a computer I'm not really reading every word in the tweet. I quickly scan through and stop when a keyword catches my eye. With a blog I have more text to scan, plus how would I even find the blog post in the first place? And with the shear amount of content on the web, I appreciate the fact that I am harvesting what others found interesting. I might not be interested in everything they tweet, but I followed them for a reason - i.e. I found them more or less interested in the same topics I am.
Twitter is as complete as it needs to be
Sure, people want A+B+C, but nobody said Twitter has to be everything for everybody. Twitter does A really well and leave B and C for others to do just as good. I am a strong believe that if you can't get the basics right, then there is no point to attempt at providing B and C. And when you have the basics nailed, why ruin it by expanding scope? Twitter is not fundamental, but it is simple and gets the job done. I used to scan blogs I follow in the morning before heading to work, now I am exposed to a larger base of articles and tweets where I am able to quickly pick out what I am interested in reading at that point. The problem with following blogs is that most of the time you won't find something interesting on them every day, you will on Twitter.
Why Facebook status updates are nothing like Twitter feeds?
This will probably change after the recent acquisition of FriendFeed by Facebook, but until it does Facebook status updates is very different and is used for different reasons. I would argue that Facebook in fact is pure vanity, I agree Twitter is too to some degree (i.e who has the more followers? who has the coolest background, who is a connector? whose got more RTs? etc.). I wouldn't scan Facebook updates on a daily basis, I would scan Twitter updates though. Twitter is kind of like a dynamic browser and social bookmarking tool. The similarity that I have seen between both is that people are using Facebook to share funny or interesting videos in my case. If I feel like watching a funny video, I would check what has been shared on Facebook.
Another major difference is that on Facebook your interests may not be aligned with your friends as much as they are with the people you follow on Twitter. For example, I got an iPhone a month ago and would like to know what applications people recommend I download. I can easily follow 20 people that talk about the iPhone and find out, how do I find such people on Facebook? and after I do I need to befriend them to be able to see their updates.
Twitter isn't supposed to replace anything, but it definitely adds a lot to certain people - and for me at least it replaced reading online news. Facebook's feed as this stage is nowhere near a competitor to Twitter. Their uses overlap in some areas but in my opinion are disjoint in most areas. Certain things are better shared on Facebook, ex. a picture of friends at your birthday party, other things are better shared on Twitter ex. a link to a specific topic that interests a fraction of your Facebook network, but much more on your Twitter network.
Twitter as a news aggregator
Twitter is a great aggregator, and works great aggregating news which explains why traditional media hopped on it. I didn't learn about Michael Jackson's death on Facebook, nor did I learn about it on CNN, I read it on Twitter. I confirmed it on CNN though and then on Facebook I saw friends' recollections of his greatest moments. On the Iran fiasco, I learned that through Twitter as well, unfortunately that weekend the media dropped the ball and I couldn't confirm any of it, but the fact that so many people were 'reporting' on it in real-time was enough to give it credibility.
Twitter became pure vanity
One thing that disappointed me about Twitter is how fast it got flooded with "experts" and "gurus", there is an expert on every imaginable topic on Twitter - obviously not all legit or credible sources of information. But I am guilty of this as well, I described myself as a "Google Maps Guru".
For me at least, I don't follow many people who just promote themselves i.e. the whole "I just ate an apple....yum" crowd - unless I know them in person or they usually share stuff that interests me. But this is the great thing about its simplicity, if I want to do some sort of social experiment about how often people post when eating an apple, Twitter would be my source for that info.
My daily dosage of tweets come from other Google maps developers, the different Google products teams, friends, legit SEO experts, news aggregators, the media and some miscellaneous people that I found interesting via RTs, FollowFridays or followers.
I agree, our attention is spread so thin these days, but because of that, if it weren't for Twitter's 140 characters could it have worked at all?