Linux, known as a powerful Operating System, especially in Networking. Linux Creates stabil, robust and powerful server, such as Mail Server and Database Server. Nowadays, a lot of parties use Linux as their servers including those who switch from Propriatery products to Linux.
Linux grow bigger and better from time to time, not just in various kinds of distro but also in capability and not just in Server but also for other aspects such as Office suites with OpenOffice.org and other Office Software. Web is an aspect which getting better in Linux, from programming languages until animation. In Programming Languages we know very popular scripts can run in Linux, PHP one of the example. we know Apache as a free software but very powerful for Web Server and also we know Nvu for Web Design and GIMP for graphics. Although still in better development and still under Propriatery software, Flash animation software in Linux, we can use, it is F4L. We also Know other GNU Public License , they are CMS (Mambo, Joomla), for forum (PHPBB) which we can use freely and still use Linux as Operating System.
In general, so many software we can use under Linux for Web Development for making beautiful and powerful Website and Web Based Application. from now on, we can move from Windows (moreover it is illegal Windows) or Mac to Linux for Web Development.
Happy Coding and Design.