I am thinking about writing a plugin for email application. It can be put on Gmail Labs. It can be thunderbird plugin or even chrome/firefox plugin. But to get the most exposure I should put it on Gmail Labs if possible. Actually, I don't know if it's possible at all. BTW, I'm aware of this. Let me know what you think.
No, Gmail Labs is not open to external contributions. However, Gmail users can add external gadgets to Gmail.
来源：https://stackoverflow.com/questions/9985378/is-gmail-lab-api-open