Via Chris Moody, Political reporter for Yahoo! News:

After watching the news and reading this from the Wall Street Journal, I once again managed to get thoroughly annoyed. Candidates who use their presidential campaigns to sell books are exploiting and profiting off voters instead of concentrating on cultivating them and offering a credible platform and maybe even a hint of gravitas.

Correct me if I’m wrong, but I don’t recall candidate Obama holding book signings instead of actively campaigning. Making money wasn’t his primary goal, holding office was, although any income from The Audacity of Hope was undoubtedly welcome.

This is not to say voters shouldn’t have or wouldn’t bring copies of Barack Obama’s books for him to sign, but it wasn’t a sit-down autograph session designed to sell a product.

Wiki:

The Audacity of Hope: Thoughts on Reclaiming the American Dream is the second book written by then-Senator Barack Obama.^[1] In the fall of 2006 it became number one on both the New York Times and Amazon.com bestsellers lists after Obama was endorsed by Oprah Winfrey.^[2] In the book, Obama expounds on many of the subjects that became part of his 2008 campaign for the presidency. … Obama announced his ultimately successful presidential campaign on February 10, 2007, a little less than three months after the book’s release. [...]

The Chicago Tribune credits the large crowds that gathered at book signings with influencing Obama’s decision to run for president.

So the crowds at the signings were a motivation to run, not vice versa.

The Wall Street Journal:

Republican presidential hopefuls Michele Bachmann and Newt Gingrich are trying to capitalize on one of the busiest shopping weekends of the year by peddling copies of their books in a pair of early nominating states.

On Saturday, Mrs. Bachmann will sign copies of her new autobiography, “Core of Conviction: My Story,” at the Radisson in Davenport, Iowa, as well as a Barnes & Noble in Cedar Rapids and the Christian Family Store in West Des Moines. Meanwhile, Mr. Gingrich will host another of his many book signings at a Books-A-Million in Naples, Fla.

In both cases, the stops are part commerce, part campaign event.

Fake candidates Gingrich, Bachmann, Cain: None were ever serious about winning the presidency, all were serious about furthering their own post-1012 careers and padding their wallets.