In VSS, one file can be shared among multiple projects. Changes to the file from one project are automatically seen by other projects sharing the file. This encourages code reuse. Use the Links tab in the Properties command on the File menu to see a list of projects sharing a file.
Branching is the process of taking a file in two directions (that is, branches or paths) at once. VSS keeps track of these branches by tracking the different paths as a project.
Note In other (non-project-oriented) version control systems, branches are tracked through extended version numbers: for example, version "2.3.9.2" is the second revision of the ninth branch of version 2.3. In VSS, however, branches are tracked with different and distinct project names.
Branching a file breaks the shared link, making the file in that project independent of all other projects. The changes you make in the file are not reflected elsewhere, and vice versa. A branch has been created: two files (the file in the project, and its counterpart in other projects) have a shared history up to a certain point, and divergent histories after that time.
After you branch a file, the Links tab does not show the link that has been broken. Instead, you use the Paths tab (also available from the Properties command on the File menu) to view the branch history of the file.
For information on how to branch and share files and projects, refer to: