This is really worth a category all of its own.  Jackie once again raises the issue linking to this guy who makes most of the points I made but better.  I particularly liked the quote from Robert Scoble:

‘[...] If you don’t have an RSS feed, your site is lame because you’ve told the connectors (er, superusers, er influentials) that they don’t matter. When I see a site that doesn’t have an RSS feed I see a site that says “Mr. Scoble you aren’t welcome here and we don’t ever want you to come back again.”’

Indeed.

Update.  And now it does have a category of its own.