Hosting and Reusing the Browser
Windows Internet Explorer's components can easily be reused thanks to its Component Object Model (COM)-based architecture. Two commonly used components are shdocvw.dll (the WebBrowser Control) and mshtml.dll (code-named "Trident").
In the majority of situations, it is better to directly host the WebBrowser rather than MSHTML. This is because the WebBrowser supports in-place navigation, history, and so on—in other words, it encapsulates the expanded capabilities of the browser. If you host MSHTML directly, you gain the use of an HTML and Cascading Style Sheets (CSS) parser and renderer, but you cannot take advantage of the browser's other capabilities.