So there are 3 problems here;
- You need a way to ensure that accounts belong to one another, otherwise license keys could just be shared around.
- Turning the application into a subscription model is problematic, as many people (including myself) wouldn’t exactly like the idea of having to pay a subscription for the storage itself, and then a separate subscription for the software to use said storage with.
- For the application to be turned into a subscription model, there would need to be some proper guarantees and liability in place for data integrity. There is a big difference in what people expect from a once-off €25 application, and what they expect from a service that charges them a monthly/annual fee. Because of this, from a legal costs and liability point of view, I wouldn’t recommend a subscription model for a piece of software of this kind, especially for a smaller company.
I think there’s possibly quite a simple solution to this; When someone buys InSync, they already get an account, where they assign their license key to a single Google account.
- Allow people to add multiple accounts in the same way and assign them to a single license.
- To prevent people from adding random people to their subscription, give the added accounts access to one another’s data in some way. This doesn’t mean synchronising data from all accounts to all machines, but perhaps a simple checkbox or a very simplistic web UI that allows files to be downloaded would suffice. This is kind of like what Amazon does with its Prime family sharing option; give all members of an account access to all payment methods – it’s a very effective way of making sure people don’t just share accounts with random friends or strangers as a cost saving measure. You want it to be convenient to have several of your own accounts on a single license, but you want it to be risky to share a license with other people. Giving access to all accounts’ data through every client that is connected to the same license would just be one way of achieving this outcome.