In response to my most recent post about authentication in aggregators, Matthew Ernest left me a comment that provides some insight into one possible implementation.

"Three words: HTTP Basic Authentication.

On the client side, I just looked at xml.rss.readService and from what I see the Radio aggregator will already accept a RSS feed URL with a username and password in it, i.e. http://username:password@server.com/path/rss.xml, and include the Authentication: Basic headers in the http call.

On the server side: .htaccess to set a password files for acces to the RSS file. Note that custom error pages should be used that are also RSS so that they'll show up in the agregator.

If you want to charge money somewhere in there, there are plenty of third party services to take peoples credit cards and manage password files accordingly. As usual, our friends in the porn industry are way ahead of us."

I'm sufficiently intrigued. When we get further into the SLS portal, I know I'll have feeds that I want to be available to our members only. I'll have to re-visit this topic at that point. Thanks, Matthew!