TextMate - a powerful text editor for the Mac
I was interested in web frameworks for quite some time and one day, like many people, I discovered the Rails video that showed a new text editor called TextMate. After it came out of beta in Oct., 2006 I jumped on and registered it (number #63!).
While it was closed-source (and still is), it was evolving very rapidly and soon included a very nice interface for plugins so people development a wide-range of them, making it much more powerful, with many languages support, VCS support and more.
After some time, the author announced he was working on the 2nd major version of TextMate, rewriting everything but it took a very long time, even making TM becoming a part of the infamous vaporware-kind of software (like Duke Nukem Forever). People started switching away from TextMate, going for alternatives like Smultron.
He then decided that he had not enough time to properly work on this alone so he finally announced both the alpha and open-sourcing of TM2.