The RSS feeds on a page should be indicated with <link rel>, so that they can be found by aggregators.
I've been wondering about this. Ikiwiki's rss buttons include a type="application/rss+xml" and link to the rss file, and this is enough for at least some auto-discovery tools to find the rss feed. But apparently not all of them.
For example, firefox requires the following:
<link rel="alternate" type="application/rss+xml" title="RSS" href="index.rss" />