The Content Rollup Web Part displays the tasks defined in each Task List within the Sharepoint Site collection and thus gives much better visibility to new or pending tasks created anywhere within the current site collection. The Content Roll Up Web Part allows to filter the results by any column, the current date and the currently logged-in user.
It is more challenging to create and display a set of like elements across multiple lists or multiple sites. Tasks could be maintained in project sites, departmental sites, and personal sites. This is the challenge of aggregating, or rolling up, content. There are several approaches in SharePoint 2007 towards overcoming this challenge. The right approach depends on a number of factors.