With Sparrow sold to Google, and the authors effectively abandoning the product, people are getting upset about it. Matt Gemell has a good overview of the reactions. Personally I always feel sad when great products disappear, but unfortunately that is live. It would be great if authors cared enough about products to find great stewards to take over their software, but that seems to almost never work. I cannot really blame the authors either: It is hard to find such people, as they could be successful doing other great stuff, and those you can find tend not to be able to pay you even remotely what other suitors are willing to offer.
I believe Marco Arment nailed it when he encourages people to help making the products you care about financially successful. After all most indies love their independence, and that will sway many not to go the big company route.
What leaves a bad taste about the sale though is that Sparrow, just as Sofa when they were acquired by Facebook, ran a sale of their software knowing full well that it has become abandonware, but without telling anyone. It leaves the impression of trying to grab as much money as they can. The honorable thing would have been to have a money back offer for all licenses purchased in the last half year.