I launched http://gardenate.com back in 2007 initially just for Australia/New Zealand and mainly for my own use (Perl with Amazon SES for sending out about 70,000 subscriber emails/month). Since then I've grown it to include UK/USA/CAN/ZA, and I wrote some related mobile apps for iOS (Objective-C) and Android. Brings in several hundred $$ per month in adwords and app sales. It used to bring in a lot more app revenue until a couple of years ago our national broadcaster (ABC) released a competing free app and ate our niche!