I've been to countless sites where you simply enter the URL (not even the rss feed url) of a blog and the site will find the feed (somehow) and import the blog. I'd like to allow users on my site to import their external blogs to be displayed. What are the basic steps to do this? Maybe cURL and look for ".rss" to find the feed url? Then what?
I think you might be referring to these lines of code: <link rel="alternate" type="application/rss+xml" title="RSS 2.0" href="http://rssurl" /> <link rel="alternate" type="text/xml" title="RSS .92" href="http://rssurl" /> <link rel="alternate" type="application/atom+xml" title="Atom 0.3" href="http://rssurl" /> which go in the <head> of your webpage. This does not import anything, it simply provides a link to the RSS feed for the browser to follow. It pulls it up like any other webpage.
Are you looking for php code that parse rss feed and display the content on your site? I've seen something like this in drupal, you can download the code and implement it on your site