Windows Phone's largest launch ever (Lumia 900) only gave them a 0.1% increase in US marketshare.

In what many considered Windows Phone's biggest month ever, WP saw a paltry 0.1% increase in market share.

March -

http://www.comscore.com/Press_Events/Press_Releases/2012/5/comScore_Reports_March_2012_U.S._Mobile_Subscriber_Market_ShareApril

April -

http://www.comscore.com/Press_Events/Press_Releases/2012/6/comScore_Reports_April_2012_U.S._Mobile_Subscriber_Market_Share

This does not sound good to me, especially with no major WP launches coming up until WP8 late this year (optimistically)