There are probably several different ways of versioning software. Some use major and minor numbers, some use alpha characters, some use both a revision and a version, the list goes on.
SysMetrix's versioning is pretty basic. It simply follows VB's Major.Minor.Revision scheme - I just autoincrement for each build of SysMetrix. For me there are only two interesting points:
1) The major number is 0, which means that it's not yet at a 1.0 release. In other words, it's still in beta. When it's out of beta and officially released it will be 1.0.0.
2) The minor and rev numbers autoincrement for each build so you can easily tell if there's a newer build available compared to what you have.