The contributed commands from the Boston College Statistical Software Components (SSC) archive, often called the Boston College Archive, are provided by http://repec.org.
The commands available are implemented as one or more ado-files, and together with their corresponding help files and any other associated files, they form a package. These packages are available at SSC.
The ssc command allows you to easily download a package. For example, when you type
. ssc install outreg
all of the files associated with the package named outreg are downloaded and installed on your computer.
Packages can easily be unistalled. You type ado dir to obtain a list of packages that you have previously installed, and then you type ado uninstall [#] to uninstall the package.
For more information on the ssc command, type help ssc in Stata or click here to view the browser version of the help file.