Enabling dynamic aggregation of content from a plurality of content
providers. The invention stores references associated with specific
display areas in a document for a particular data source. Responsive to a
request for the document, the invention retrieves the references
associated with the data source and dynamically inserts the references
into the appropriate display area of the document. A client renders the
document by obtaining the content associated with the references. In an
embodiment, the invention includes a web service for cobranding a login
user interface for a user authentication system. The web service places
cobranding content provided by an affiliate content provider and sign-in
user interface content provided by a user authentication service into
different frames of a single web page.