[rz2k]

I think there's a quasi-cynical opportunity in developing any category of product that is regularly acquired then quietly allowed to die. For example, it seems like not having a lot of people using a client like Sparrow was worth more to Google than people are willing to pay for an alternative to the browser-based client. Furthermore, because there are a lot of corner cases in IMAP that you must be sufficiently skilled to address, and users have high expectations about reliability, making a good enough client to gain traction is a good sign about your value as an engineer for the acquiring company.

Perhaps a great feature to make such a client's slow death through acquisition even more desirable would be seamless end-to-end encryption so that users' emails provided no marketing data.