Back in October, just before the release of Windows 8, Google had officially released the search app for Windows 8. The search app had been neatly designed with many features including voice support and the results were displayed neatly. Now if you want to search other popular sites like Bing, Wikipedia, Facebook, Twitter etc independently then you can probably try out SearchAll freeware app for Windows 8.
All your favorite search engines are present at one place, enabling you to search contents much faster and efficiently and comes with an easy to use interface.
To search, type the search query and click on the logo of the site you want to search. The app also comes with a built in browser to open links from the search results.
You can search for contents across following websites:
Overall, SearchAll is a very good app to search multiple sites at one location.