My geeklog site, freeafterrebate.info, has been running for almost a year. It is an information service that tells about free-after-rebate deals at online merchants.
I've written a number of add-ons to geeklog, including the ability to automatically change the category of articles on a pre-determined date. When a rebate expires, the category is automatically switched from "software" to "expired", for instance. Another program automatically creates an e-mail newsletter based on the stories added to geeklog within the past week.