I love this idea and have also been thinking often of similar email-based solutions. Very cool, but here's some feedback anyways.<p>The main problem is inevitably the syntax. It very quickly becomes too complicated, and with email you have the additional problem that you don't get instant feedback on submission.<p>In your case, the syntax might be simple enough to not be an issue. However, for many people (me included), it would probably still be easier, less error-prone and quicker to use a web interface with instant feedback. And since the type of person using this service is likely to be quite fast and proficient, there's little advantage to your solution over a web-based interface.<p>I do think there's a way to add value for users like me, though. Three things I like about email could be leveraged (more):
1. I always have email open
2. I tend to use email for quick, short messages that have more permanence than chat.
3. I tend to use email to keep track of things. For example, I don't open my billing app (Billings OSX) to see if I already sent out an invoice, of if it's due. Instead, I just search in gmail to see <i>if</i> I sent out the invoice, and <i>when</i>.<p>What you could add to this project to make it worthwhile to me, and I suspect many others, is the idea of <i>partial</i> invoices. I would send an email with one or more items, and these would then be added as items to this 'account'. Finally, I can send out an invoice with the total items by logging into your web interface, or through email.<p>It would greatly benefit me to send an email with something like:<p>"50 mins, implement login system, clientname"<p>It would be vastly preferable to my current approach where I load up the application, navigate to the client, and add the item, or alternatively where i add this item to my task app.