Ask.com is currently running a television ad that features no spoken
script. The ad begins "Why is Ask.com the fastest-growing search
engine?" in white text against a red background, and the ad continues
with snippets of newspaper reviews, etc. There is an electronic/techno
background soundtrack. What song is playing, and is it available for
purchase to consumers?

I think it might be taken from, or a modified version of, William
Orbit's 'Water Babies'.

I believe that comes from his 'Stange Cargo' series of albums.

I think you are close on the song, but I believe the song is called
"Water from a Vine Leaf".  Unfortunately, I have only seen (heard) the
commercial once, so I'm not so sure myself, but the song sounds very
familiar.  Check out the following website (thanks to franklinhpd-ga I
would never have found this either)  http://www.williamorbit.com/, and
click on the "even more audio" tab from the menu to listen to various
William Orbit songs.

You can also find the song, as well as "Water Babies", on iTunes if
you have an account.  Unfortunately however, you can't just buy the
one song for $.99, you're forced to buy the whole album for $9.99
(thanks to iTunes's infinite "wisdom").