knock someone's socks off

「（多くの場合いい意味で）驚嘆させる」。いい意味で驚くとなぜ靴下が脱げるのか、哲学的に考える今日この頃。全然関係ありませんが、激しい交通事故だと靴が脱げるらしいです。

Is Backup on Apple’s Back Burner or Simply Abandoned? on theAppleBlog

If you really want to knock my socks off, include encryption options like you did with the latest iPhones.

For the meaning of "back burner" in the title, please see this blog post.