Dan Frommer:

Specifically, while the num­ber of smart­phone own­ers in the U.S. — accord­ing to com­Score — has grown to 104 mil­lion from 45 mil­lion, the num­ber of Microsoft smart­phone own­ers has declined to roughly 4 mil­lion, from 7 million.

WP7 app devel­op­ers will now think twice before embark­ing on another app. And that will only accel­er­ate the decline.

Microsoft made a huge strate­gic mis­take by being rigid on pixel for­mat (800×480). The goal was noble: to main­tain a con­sis­tent expe­ri­ence across dif­fer­ent WP7 smart­phones. The mis­take? 800×480 on dif­fer­ent dis­play sizes mean the visual expe­ri­ence will be dif­fer­ent. Fonts will be ren­dered big­ger on a big­ger dis­play, smaller on a smaller one. What Microsoft should have done instead is to be rigid on res­o­lu­tion, say 300 ppi. That way fonts, icons, etc. will have the same size regard­less of how big or small the dis­plays are. This is how you ensure a con­sis­tent visual expe­ri­ence across all WP7 smart­phones. Big mis­take Microsoft.