I would say, contrast focuses only on the difference between the entities being contrasted, while compare can mean, you also focus on the similarities. Not sure, how you use the words, though.
It was a sarcastic remark. My original comment's gist was that all of the naysayers, at least with respect to the amount of funding required, are basing their analysis on a faulty assumption. So far, we've seen a very narrow niche of people, with very specific interests, fund successful kickstarters on the order of $1,000,000 to $10,000,000. In _contrast_, the demographic of people that would likely be interested in funding cancer research is potentially 1,000 to 10,000 times larger than the 18-35 year old, white American male STEM worker with disposable income and a poor understanding of the realities of electronics manufacturing demographic.
My Bad. Though, the original comment "compare cancer with Pebble" didn't deserve a reply. Just trolling, you're comparing funding campaign building both, not the experiences of both.
Thus, $1,000,000,000 is not unreasonable at all.