cvs tag vs. rtag

[Laird Nelson]

Can someone give me a pointer on when to use cvs tag vs. when to use cvs
rtag?  I know, for example, that cvs tag doesn't show up in the history
file, and that cvs rtag requires you? I think? to feed it the revision
number of whatever you're tagging, thus preventing you from saying "cvs
rtag the tree the way it is now".  What common situations is each
command used in?

Cheers,
Laird