Wow, thanks for all the reactions and enthusiasm. Try to respond to most of it in this reply, without repeating all the quotes of others.
Watches: a watch can not be used solely without the phone to correctly measure height, unless you tape the watch to the board and the watch should have accelerometer and gyro as well. The thing is: it has to be mounted to the board. We did a lot of testing with chest mounting, but it didn't work to well. Maybe it's gonna be possible later, but the early findings indicate that this will be very very hard without something mounted to the board
Subscription model: As stated in the FAQ we probably will introduce a subscription model in the future. But at this point there is no need for that, and we also would like to see the app growing as fast as possible. Probably adding a premium/subscription model later on. I totally agree that subscription model is the way to go in the long run. Selling mounts is not that interesting since it has no continuity in terms of revenue. Making money of this has never been my goal for this, justed wanted to see if I could make work out of my biggest passion: kite boarding. Considered doing an instructor course as well to make work out of kite boarding, but ended up programming again
. It all started as a big challenge: can it be done. This doesn't mean I don't think long term, and how it looks now I will be working on this fulltime for the foreseeable future, so beside hosting costs I probably need a income from this as well. But I recently sold my previous IT company which make it possible for me to 'work for free' right now. Good to hear that I subscription fee of a small monthly/yearly amount is considered fair. I don't consider this to be a hobby project (in terms of taking this serious), have worked on it for months on 60-80 hour basis per week. New functionalities will drop every few weeks/months
Merging leaderboards: This would be very hard because you can't compare WOO to Surfr. Surfr. is measuring 20-25% lower on average. Of course it would be easy to correct this, but we believe in our own measurements. We will publish some info about this soon, we're going to create a test setup with poles and jump right in front of it (think like jumping pole stick). I think people will start using this beside their current sensor at first. In just 2 days time already hundreds of people pre-ordered the mount, which is way more than I expected. So I guess and hope the community will grow rapidly.
Offline/Online: the app can operate offline and record everything offline. All calculations happens offline on the device. Live will only work with internet connection (obviously). Reception on the water so far has been pretty good.
Future development: please PM me ideas of post them here for the app. I think there are so much possibilities with the combination of internet + GPS, accelerometer and gyroscope.