Sharing a file means it exists equally in all the projects to which it is shared. Branching a file breaks the shared link, making the file in that project independent of all other projects.
Note To view projects sharing a file, click the Links tab in the Properties command on the File menu. To view the branch history of a file, click the Paths tab in the Properties command on the File menu.
To branch and share a file on one operation:
In VSS Explorer, select the project into which you want to branch/share a file.
On the SourceSafe menu, click Share to display the Share dialog box.
In the File to share list, select the file you want to share. If the file you want to share is not displayed, select the project containing the file from the Projects list.
Select the Branch after share check box.
Click Share to display the Share File dialog box.
In the Comment box, type a comment describing the branch/share, if desired.