Windows defines a number of directories for specific things.

One of those directories is a directory that a well-behaved Windows application should use to store user-specific data (e.g. a list of recently open documents by this user, customization information etc.).

Usually this is a hidden directory C:\Documents and Settings\$UserName\Application Data. Most applications choose to create a sub-directory named after application. Bigger companies, like Macromedia or Microsoft choose, to use 2-level hierarchy: $CompanyName\$ApplicationName.

In .NET framework, Application object (from System.Windows.Forms namespace) has a static property UserAppDataPath that returns a string naming directory for storing user-specific application data. However, designers went overboard and used 3-level hierarchy: $CompanyName\$ApplicationName\$VersionNumber.

Adding version number is a mistake. When user upgrades the application, he doesn't want to loose his settings and customizations.

Another way to get this is to use Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData) and append your application name, like this:

class Util
{
    static public string GetUserDataPath()
    {
        string dir = Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData);
        dir = System.IO.Path.Combine(dir, "MySoftware");
        if (!Directory.Exists(dir))
            Directory.CreateDirectory(dir);
        return dir;
    }
}