Regarding the timezone setting, since user can set up reminders in Marrily to get notified (via email and through their phone), it's critical to know their timezone so that the application can send out the notifications at the right time. The timezone dropdown on the sign up actually tries to be smart and pick out the timezone based on the user's current time.
You're right, Marrily at this stage is not yet ready for international usage yet. All the time-related fields are parsed as %m/%d/%Y (m/dd/yyyy). Once the main app is finalized, I'll add more international support and customization (like time dislay format, and how to format the contact name: "First Last", or "Last, First").
Regarding your comment about the Expenses, this is probably the weakest part of the app. I built a prototype that lets user enter in their budget for each categories and track their expenses accordingly, but I ripped that off since I didn't think it was god enough to release yet. I'd need to do further research and ask people for feedback before building this feature again. In the meantime, I'll add the "provisional" flag to the expense to keep track of provisional/actual. Also, do you think the ability to link the payment to the vendor helpful?
Thanks for all your comments. I really appreciate it.