I wasn't presenting the be-all, end-all criteria for determining which features to implement, just that there needs to be one in order to make a decision. Your example is likely better, and I'm sure Microsoft's taskbar team uses their own method:
"Part of the hard job of product design is deciding which 20 features you have the resources to pursue and which 180 to leave for next time. If you choose the right 20, people will say you're the best new UI feature in Windows, or even the best Windows 7 feature, and they won't mind too much that you didn't get to the other 180."[1]
I think single features can certainly sway a purchaser. If I like the OS X notification center quite a bit and its integration with 3rd party applications I use a lot, then it may well cause me to lean in the direction to purchase a MacBook over a Lenovo. Of course they're all taken as parts of a whole, but it's still conceivable that people may not be able to perform their job/task in a way that they are accustomed to without X feature.
In addition, while some features may not sway you, it is not unlikely that you are an exception to the rule.
"Part of the hard job of product design is deciding which 20 features you have the resources to pursue and which 180 to leave for next time. If you choose the right 20, people will say you're the best new UI feature in Windows, or even the best Windows 7 feature, and they won't mind too much that you didn't get to the other 180."[1]
I think single features can certainly sway a purchaser. If I like the OS X notification center quite a bit and its integration with 3rd party applications I use a lot, then it may well cause me to lean in the direction to purchase a MacBook over a Lenovo. Of course they're all taken as parts of a whole, but it's still conceivable that people may not be able to perform their job/task in a way that they are accustomed to without X feature.
In addition, while some features may not sway you, it is not unlikely that you are an exception to the rule.
[1] http://blogs.msdn.com/b/oldnewthing/archive/2010/05/31/10017...