On Linux, neither Chrome nor Firefox are working for me, yet:

    $ host _why.usesthis.com                                                       
    _why.usesthis.com has address 74.207.245.100

odd.

[Edit: Looking at darshan's post below, I understand why: host (part of the BIND distribution) uses its own resolver; everything else goes through the system facility (i.e. glibc). I still don't know how to fix it, though.]