A friend and I are trying to put together a very basic finance/accounting app, where anyone will be able to easily record their expenses and income. We were looking for an existing app for personal use, but couldn't really find anything that's very simple in features and usability. We found ledger (http://wiki.github.com/jwiegley/ledger/) to be the closest, but want something that's Web-based. We are looking to build the app exclusively for "tiny enterprises" (i.e. personal use, households, single person businesses, small businesses and early startups).

The most basic feature will be the ability to record (or upload a CSV with) income transactions and expense transactions; and generate a simple summary report at any time.

We'll really appreciate any ideas and suggestions which we can address in our product, mainly:

1. Do you have a use for such an application (basic accounting, no frills, no extra features)? If so, what one feature would you like to have and what one feature you wouldn't want in the app?

2. Should we base it on single-entry or double-entry accounting? Or maybe something altogether different.

3. What sort of report(s) do you envision, if you were to use such an app?

4. How do we deal with data security? Many individuals and small businesses may not be comfortable with us storing their transactional data.

5. If you were to use such an app, where will you primarily access/use it for its full worth - desktop/laptop, smartphone, tablet?

Any guidance, tips or frank opinions are welcome! Thanks in advance.