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GitHub is the largest code host on the planet, hosting over 21.4 million repositories. It is unarguably the most widely used tool by developers worldwide.
SpecsUpdate
Pros
Pro Nice and usable UI
GitHub's UI is clean and intuitive. Each view is designed to not fill the screen with useless information.
For example, the repository view displays only the most crucial data about that repo - on the top it displays the number of commits, branches, releases and contributors. When clicked, each of them will take the user to a page that displays more detailed information.
Pro GitHub makes it easy to find open source projects
GitHub is the largest host in the world for open source projects. Developers from all over the world fork and work on countless projects hosted on it.
GitHub's search box is a powerful tool that allows developers to find open source projects in areas they are interested in and where they can immediately start to contribute.
GitHub also has a page dedicated solely at exploring and finding open source projects, grouping them by each topic they cover. In the same view, GitHub displays trending repositories and sorting them by day, week or month.
Cons
Con Not built for finding and installing software
Github is first and foremost a code host. It's built around the idea of hosting code and collaborating on working on software projects. Installing software is not as easy and you need to have some knowledge on compiling and building code in case you want to install a project for which the maintainer has not released a compiled binary.