Every software developer has a dream, dreaming that one day people's life can be changed due to his/her contribution, so do I. I used to think that my killer application must be like a superman, who can save the world from hunger or disease or any other tough issues——or we can't say it changes the world.

But, you know, toys change the world of children, so why can't e-toys change the world of internet? A friend who worked as a PM in Microsoft for nine years told me that a wonderful product can be very very simple, just to solve one simple problem accurately and elegantly. I have not been able to imagine such a software toy until I found Twitter.

First of all I have to declare this post is not ad, I'm just telling you my feeling. What is Twitter? It is a so-called mini weblog, one user sends update of what he's doing, all the other users see it. Twitter is quite simple and even a bit of crude, but it's free and open to all users and developers. Whenever and wherever you have access to internet, you can tell people what you're doing via Twitter. Recently, Twitter has become one of the most popular applications. Someone may ask you, "don't your thumbs hurt yet?", that does not mean sending SMS via mobile, they really want to know if you're crazy on mobile Twitter.

Someone who's not using Twitter may wonder why it's so hot, and someone who's new to Twitter may find it not interesting at all. Obviously not everyone loves to share life with others, follow or get followed, they prefer to stay alone. While more and more people are joining one or several SNS communities, different people would choose to stay in different places. For instance, young undergraduates join xiaonei.com to find friends from same school, while kaixin is the first choice for white collars to kill spare time by playing web page games, and job-seekers and head-hunters love LinkedIn.

So what are those guys hanging around Twitter all day? What can I gain from being a Twitterer? I have several reasons, but may not be suitable for you.

• Another card of you, just like an email address or a blog url, part of your profile.
• Faster sharing. If you're a Twitterer you will see many people are sharing interesting posts or videos from various sources by pasting urls from time to time, it's faster and of more freedom.
• Getting up-to-date news. More and more organizations have their Twitter accounts in order to make a promotion and publish information. In this way, Twitter can be a "Google Reader". For example, I've followed IBM Research and a clinic research institution for tech news, and followed hoopchina.com to get the latest NBA rumors, find it really useful.
• The last may be where the biggest fun comes from. Famous people also tweet, we fans follow. Politics enthusiasts can follow Obama, soccer lovers will find C.Ronaldo, metal music fans may chat with Kaiser Kuo. Think how sina blog make its promotion by inviting all kinds of stars to set blogs at blog.sina.com. In compare with blog, Twitter brings grass roots and big shots even more closer.

These days I've been introducing Twitter to my friends, most of them start to get the fun of   "What Are You Doing?" and fall in love with this e-toy. It may not fit you, but why not have a try?