When you download some software or application from sources other than Ubuntu Software Center such as downloading the latest version of Skype, it comes in .deb (debian installer files). Installing .deb is not really a tough task. Just by double clicking on the .deb file, it opens Ubuntu Software Center to install the application. And that could be a little problem.
Ubuntu Software Center is known for eating resource. It is heavy, takes ages to load and makes your system crawl. It may be good for finding application but it certainly is not worth using just for installing a .deb file. Earlier Ubuntu used archive manager for installing .deb files but with time it changed and now Software Center is the default application for it.
Now the question is why use Ubuntu Software Center? If you are concerned about performance and use several ways to improve Ubuntu speed up such as using apt-fast and preload, you must consider a light weight alternative to install .deb files. And this is where Gdebi package installer helps you. Gedbi is a light weight program for managing .deb packages. It works very well with missing dependencies.
Install Gdebi Package Installer in Ubuntu:
Open the terminal (Ctrl+Alt+T) and use the following command:
sudo apt-get install gdebi
The next time you go for installing .deb file, just right click on it and choose to install it with Gdebi. Cheers :)