Its not helpful, they aren't complying with the relinking clause. I don't think there's any way to use LGPL with closed source on mobile app stores.

I'm assuming you didn't read it. I will give you benefit of the doubt since the Sparrow page was pulled after Google acquired them.

Sparrow made available on a website the necessary binaries for the user to relink if they so chose thus complying with the terms of LGPL.