Mint's founder on virality (paraphrased): his product had essentially no virality (no one shares their bank stories with their friends) so he focused instead on good old PR: making sure he'd be in the news as much as he could.
I think Josh's point was not that you needed virality. Virality is just one way to get distribution (albeit a very efficient way). Josh's point was that distribution (aka Customer Acquisition) is hard and you can't just 'bolt virality on' as an afterthought.
So much for virality :-)