EDGAR Index is probably the most well thought through RSS-based company I’ve seen so far (other than the fee-based aggregators).

The site provides subscriptions to RSS Notification of SEC Filings via customized RSS Feeds. The site does a really nice job of explaining how this works and why it is the best way to do this.

I’m looking forward to some analysis within the community of how the custom RSS feeds work and whether there are any security issues.