Hi Luc,
for a one way publishing, I can think of two approaches :
a) the "cleanest" way for a content syndication seems the RSS feed approach. Supply your space, which containts the content, with a proper RSS template. Commenting Function would not work within alfresco, though, but would have to be done by your frontend
b) deploying a "website", containing just the parts inquestion, in the path of you main application. Check with the WCM docs on a HowTo, i havent got around to that yet.
If you want to store the comments and stuff in Alfresco as well - you would need redirect your users to the alfresco server or write a webservice api, which reads & writes from/to alfresco.
Hope that helps,
Norgan