Firebug, once the most preferred development and debugging tool for the web developers, may become irrelevant soon. If you take a look on Firebug’s usage stats, you will be surprised to see that there is a significant drop in the number of users over the past few months.
There may be many factors behind this change. First of all, Firefox itself has lost a significant fraction of browser market share because of the Google Chrome. Chrome has native support for powerful and integrated developer tools, which does not require installation of any extension or plug-in.
Moreover, Firefox team is working on a new project “DevTools”. This project is aimed to bring various development and debugging tools in Firefox. Starting with Firefox 6, a new “Web Developer” menu has appeared in Firefox with the tools like Scratchpad, Web Console etc. Upcoming versions of Firefox have many more such tools like Style Inspector and Editor. Read this article on Webmonkey to know more about these tools.
Earlier, the lead developer of Firebug project, John Barton, had left the project to join Google. On that time, Mozilla announced to support Firebug directly.
I believe that with the introduction of new native developer tools in Firefox, Firebug will just become irrelevant.