I have looked, but i can't find information on
installing hula. I would like to use the email
notification feature, but i'm not sure how even
to begin to install a plugin.

First off Hula isn't a plugin, it's a separate application that uses the XML-RPC feature of JSPWiki.  I'm going from memory here, but as I recall, you just download Hula, and unzip it.  Somewhere in there is a shell script (batch file) that you can use to start the email notification demonstration application.  You pass various arguments to the app to tell it where your JSPWiki server is located, etc.  It works, it's easy.  I chose not to use it as I did not like having to run a separate application to get this feature.  Further, it was written as an example of how to XML-RPC not necessarily production code.  I wrote the EmailNotifierPlugin as use it for our intranet wiki's.  You decide which is best for you. The EmailNotifierPlugin doesn't allow you to subscribe to specific page changes, it always reports all changes, further it has startup issues as it only starts after someone requests the page on which it is housed.  The reporting all changes is not a big deal to me (obviously) and the startup issue is irratating but if you put the plugin on Main or ~LeftMenu it's not an issue (There's a difference between what page the plugin is on and the page it reads for subsccriptions).   --JohnVolkar

Sorry, i am an idiot. I thought the  EmailNotifierPlugin was part of 
Hula, but i see now there was just a link path between them.
Having implemented a similar feature for UseMod, i know our users
do not want to be notified of all changes, because that was my
first implementation. 

What i ended up doing was putting a user subscription list at the bottom 
of each page, using a syntax like [email UserName,UserName].
Also, you could put your user name at the bottom of a category page
and get email related to page changes related to categories. I don't
really know how to do all this yet in jspwiki. I noticed the user
account doesn't have an email address. If it did then user names
could be used instead of email addresses. Actually we have user accounts
elsewhere. I have been pondering how to use those as well.