The first commerical app I built myself was called Track My Ride, http://www.trackmyride.com.au. It earns me a fair slice of pie each month but nothing to retire on. Track My Ride was focused primarily on the local market that I could direct market to. My second app Rocket Mail Merge http://www.rocketmailmerge.com was actually born out of the need for easier invoice creation for my first business. It is targetted at the international market this time, primarily the US. I finished its coding at the end of last month. It's fully functional but I can't release it out of it's 'open beta' due to the abysmal lack of international credit card processing for Australian startups. It has taken so far 6 weeks to get approval from the bank, and that approval is still pending with no ETA in sight. I plan to write a topic on that in due course but not before getting my approval haha. Once I launch it I'll be writing a Show HN on it. It would be great if people found it as useful as I do.