Update Site Plugins
We currently have 2 update sites which are used to deploy our uDig core and community plugins. Our update sites are feature-based, so a feature and branding plugin are required to publish your plugins (plugins should be grouped logically based on a functionality they provide – if they are not related you should break out another feature and branding plugin pair).

The update site plugins are net.refractions.udig-site and net.refractions.udig-site.community.
They are published here:
uDig Core Plugins: http://udig.refractions.net/update/
uDig Community Plugins: http://udig.refractions.net/update-community/
(eclipse looks for a site.xml file at the above locations)
Preparing the Community Update Site
Sanity check
Make sure you have all the appropriate plugins, features, and branding plugins in your workspace! The site contents should look something like this:

If you see jar files instead of features, you do not have the features correctly imported (you may be able to get away with this if you are only publishing a portion of the site, as the update site is probably smart enough to use the existing jars on the server – but you certainly must have the features included for any new plugins you are publishing).
Adding a new feature
In the site.xml page, select the category you would like to add a feature to and press the "Add Feature..." button. Select the feature you would like to add.
Checking feature dependencies and appearance
For each feature, ensure that:
- the feature properly declares its dependencies (this is important so that older versions of uDig visiting the update site don't try to install these plugins when their source code might reference methods which don't yet exist).
- ... dependency versions ...
- it references its update site
- the feature.xml Overview page for the feature should have the values Update Site URL = "http://udig.refractions.net/update-community/" and Update Site Name = "User-friendly Desktop Internet GIS Community Updates" for community plugins, or "http://udig.refractions.net/update/" and "User-friendly Desktop Internet GIS Updates" for uDig core plugins.
Publishing the Update Sites
Now that everything about has been checked, we are ready to publish!
On the site.xml for the update site, click the "Build All" button.
...
Upload to http://udig.refractions.net/update/ or http://udig.refractions.net/update-community/ as appropriate.
—
TODO: figure out which fields in the features, plugins, and branding plugins appear where during the "install new features" process.