Many many users are affected by android apps not showing in their Market, just because they have a screen with a different resolution that is not the most common one.
this is the case of HTC Tattoo, with its 2.7" QVGA screen.
But this can be easily fixed by app makers, by simpling including this litte code in their manifest.xml
<uses-sdk android:minSdkVersion="3" /> <uses-sdk android:targetSdkVersion="8" />
<supports-screens android:smallScreens="true" android:normalScreens="true" android:largeScreens="true" android:anyDensity="true" />
with minSdkVersion="3" you are still supporting Android 1.5, and with supports-screens android:smallScreens="true" you tell Market that it will work in small screens too :D
Everyone wins.
Currently supported resolutions and densities byt the SDK:
1.QVGA (240x320)
2.WQVGA (240x400)
3.FWQVGA (240x432)
4.HVGA (320x480)
5.WVGA (480x800)
6.FWVGA (480x854)
* A set of three generalized sizes: large, normal, and small, and
* A set of three generalized densities: high (hdpi), medium (mdpi), and low (ldpi)