Why is pollster Rasmussen hawking Palin's book?

Last week after reading Scott Rasmussen's sky-falling-on-Obama polling piece in the WSJ, I asked, “Since when do serious, 'independent' pollsters write columns urging the president to ”shift right"?, which is what Rasmussen did.

Now, in the wake of his recent posting, I have to ask, since when do serious, 'independent' pollster hawk partisan books in their survey write-ups?

This week Rasmussen arrives with (surprise!) a pro-Palin poll just in time for her book release, and at the same time when other pollsters are finding a clear majority of Americans don't think Palin is qualified to be president.

Not only is Rasmussen's new survey a stroke of luck for Palin, but note this passage [emphasis added]:

Sixteen percent (16%) of all voters are following news about Palin's book release very closely, and 20% say they are likely to read it. That latter figure includes 31% of Republican voters. (To order the book, Going Rogue, click HERE).

Huh? Pollster Rasmussen is now pointing people to Amazon to buy a partisan politician's new book? I'm guessing Gallup does not do that.