I've recently extended PageComments using the method figured out here: http://silverstripe.org/general-questions/show/266651#post266651.
I added the email field to display the commenters' gravatars.
Next thing I did was add a method to my extended PageComments class called GravatarURL, which generates the URL from the new email field. I can access this from my custom comments template in a control Comments block, nice and easy.
My question is about good practice, as my MVC understanding is a little grey in areas.
Is it acceptable to stick my GravatarURL method in the extended PageComments model, or should I extend PageComments_Controller and put the method in there?
Sure it works as it is, but I think doing things right is important... Thanks!