Well, first of all, even though what he says about "needing to recompile all
pages that reference that control" is technically true, that is not as much
of a hassle as it sounds like. This is because a Solution is divided into
Projects, and each project is compiled separately (1 Project is compiled
into 1 *.dll). Because when making a control it is usually put in the same
Project as the pages that use it, you will normally end up recompiling the
pages that use it at the same time you compile the control. If you do end up
making a control that is not in the same project as the pages that use it,
or if you have multiple projects that use the same control, you can either
compile the entire Solution (this is the same as compiling all your
projects) or individually compile the Projects that use the control. How
many Projects you have will depend on how many different areas your site
has. It is possible to do a large site with just one Project, but it is not
usually recommended if you have areas of your site that are unrelated. But
since all the *.dll files go in the same directory on the web server anyway,
what I usually do if a control is used by more than one Project is compile
the solution and upload all the *.dll's, it only takes a couple minutes
anyway. You will find this easier to understand once you've been using
ASP.NET a little longer. Good Luck!