Paydirt is within it's full rights not to support IE9 when it's customer base doesn't really use it.
The problem is that the author notices most things work (border radius) but doesn't realize that IE9 is missing stuff we expect modern browsers to be able to support. Placeholder text and simple gradients are both not supported very well and that takes time and effort to build into your product. It's not about 90%, it's about getting that last 10% to work just right so the experience is clean and smooth for everyone involved.
IE10 might be another story, but last time I checked IE10 isn't out yet. But it seems to me that Microsoft is always one step behind.
The problem is that the author notices most things work (border radius) but doesn't realize that IE9 is missing stuff we expect modern browsers to be able to support. Placeholder text and simple gradients are both not supported very well and that takes time and effort to build into your product. It's not about 90%, it's about getting that last 10% to work just right so the experience is clean and smooth for everyone involved.
IE10 might be another story, but last time I checked IE10 isn't out yet. But it seems to me that Microsoft is always one step behind.