1. A method comprising: receiving, by a computer system, a user request for a first web application; retrieving, by the computer system, markup data for the first web application; converting, by the computer system, the retrieved markup data into markup fragments containing application markup and at least a first adaptive tag; interpreting, by the computer system, the first adaptive tag to indicate a pagelet web application; obtaining, by the computer system, code from the pagelet web application specific to the requesting user; based upon the obtained pagelet web application code, assembling, by the computer system, a page of the first application from at least data for the pagelet web application and the application markup obtained from the retrieved markup data; and providing, by the computer system, the page of the first application to the requesting user.