Microsoft Case: InfoSpace
InfoSpace Selects Silverlight to Power Toolbars (via Sam Chenaur, Moving the Needle)
Silverlight Extends The Toolbar Experience (via Artefact blog)

Rich user experience and engagement.
Artefact and InfoSpace collaborated to design and develop a brand new toolbar to attract new users and retain their current users of Nation.com. By extending the experience from your typical webpage, the Nation Toolbar engages users with "packages" of wallpapers and recipes (more to come) generated by Nation.com search results. The results are based on an aggregation of the best results from other web search engines including Google, Yahoo! and Microsoft. Using Microsoft® Silverlight™ technology, Artefact was able to design and test through the Rapid Iterative Test and Evaluation (RITE) methodology a new class of rich internet applications (RIA) both visually and functionally. Gavin Kelly, Principal and co-founder of Artefact wrote:

We’ve been quick to adopt Expression Blend because it helps us close the gap between design and implementation. Instead of spending three weeks on specifications or ‘wireframes,’ we can spend that time delivering a working prototype. Just as important, the designer’s vision remains intact throughout the development process.

A case study of the entire process can be found below.

Case study abstract:
InfoSpace must deliver highly engaging, interactive Web browser toolbars to attract and retain users for Nation.com, its new metasearch property. In addition, to drive user adoption, the company must scale customer acquisition across a large number of content verticals for those toolbars. The company is achieving both goals by using the Microsoft® Silverlight™ browser plug-in to implement a toolbar “shell” together with a large number of button “packages” from which users can choose. Strong results to date have validated both the company’s business model and the value of Silverlight as a technology capable of delivering compelling user experiences, scalability across content verticals, and affinity features that will make the toolbars and Nation.com “stickier”—as required for InfoSpace to increase customer acquisition and reduce its cost per acquisition.