Insider trading of stocks is very valuable information. Knowing which executives are selling and buying is a very useful indicator for the millions of people who are casual investors.
Yahoo Finance insider trading data is never better than a few days out of date. Yahoo Finance, MSN Money and Google Finance all purchase their data from a company called Edgar Online that charges fees for access to data that is often not up-to-date.
I wrote a back-end application to constantly monitor the Securities Exchange Commission's (very busy) RSS feed for Form 4 releases and then fetch and parse related documents for the filing (with a bit of YQL thrown in to speed things up).
Users can sign up to receive email alerts whenever a stock they own is traded by insiders. By letting people know immediately, rather than potentially weeks later through Yahoo Finance or by chance browsing of the somewhat arcane EDGAR system, who is doing what with the companies they own.
This hack is a (effectively) real-time system that provides functionality that doesn't exist for the casual investor at no cost and with timely delivery of the news.
Although it was fun making this application, it would be better if the data already existed. To enable anyone to access and use the real-time insider trading data, I created two YQL tables. The first table allows lookup by stock ticker and the second allows lookup by the insider's name (or searching for their name). Additionally, the source code for this project is available as a zip file for anyone that would like to see how the system was built or for improving its functionality.
Although the system works in real-time, today is Saturday and the markets aren't open. In order to make this a more interesting demonstration, I've set it to replay yesterday's events as if they were occurring today. If anyone would like to signup for alerts, you'll get yesterday's news today. I recommend Netflix (NFLX), Berkshire Hathaway (BRK.B), Sybase (SYBS) and Carrizo Oil & Gas (CRZO) since they all had filings yesterday afternoon.