In working with a large International Company with 100s of sites I needed to activate features on existing sites where they haven't been stapled. I have included a simple method below. In this example used the RadEditor from Telerik you gotta love the .NET controls from Telerik

1. STSADM -o enumsites to collect all existing site URLs. We cleverly strip out the site URLs from the (I hate) XML output. We then save these URLs to a text file (one URL per line) and use this to feed a FOR loop on the CMD shell.
2. STSADM -o activatefeature -id 747755CD-D060-4663-961C-9B0CC43724E9 -url [site URL]

   To activate the RadEditor for SharePoint lists for a given site (initially this will activate the tool for Mozilla users only).

3. STSADM -o activatefeature -id F374A3CA-F4A7-11DB-827C-8DD056D89593 -url [site URL]

   To activate the RadEditor for IE users.

Where did we get those ID strings you ask? Look in the "Feature.xml" file in the following locations:

• C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\FEATURES\RadEditorFeature
• C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\TEMPLATE\FEATURES\RadEditorFeatureIE

The feature ID is listed in this document between the Id tags.

-Ivan