Every time a new user discovers your service, that is your launch date. So you'll have a series of them. The more you build "launching" into something big the m

Every time a new user discovers your service, that is your launch date. So you'll have a series of them. The more you build "launching" into something big the more expectations you will have around it. The really hard thing is marketing -- getting people to know and then care about your service. Get the tech stuff out of the way and move onto this. It is hard. The first people who use your service will give you invaluable feedback. Stick a BETA on it somewhere and go live ASAP.