In development discussions surrounding the Second Life viewer's Web-support and internal Web-browser, WebKit has been a frequent discussion item. WebKit was originally derived (by Apple) from the Konqueror browser's KHTML software library and now functions as the core of Apple's Safari Web-browser. A number of companies have extended and adapted WebKit over time. A primary sticking point with adoption into the Second Life viewer, however, involved the terms of WebKit's software license.
Now that the licensing barrier has been overcome, work on integrating QtWebKit into the viewer is proceeding apace, as Linden Lab works in conjunction with Torch Mobile (makers of the Iris Browser) to finalize the integration, and sort out a few lingering issues.