If you are webmaster, Twitter Bootstrap is a quick and easy way to build websites. I am sure you have heard about and used content management systems (CMS) like Drupal, Joomla or Wordpress. But this is different to a traditional CMS system.
They have done the hard work for you. They have done the CSS and Java Script and useful components. It contain useful templates (Marketing site, Fluid Layout and etc) so you don't have to waste time fixing the layouts and making them compatible with all the web browsers. You can even build responsive website for any computer device.You only need to download the 83 Kb file, unzip it copy it to main web directory and start building the website.
No need to talk more everything can be found here and I am sure it is going to make your web developing life much easier and smooth.