The $17 mark is because one guy suddenly spent hundreds of thousands on coins in the last few days.
Source?
And if true, then why did he do it? Like anyone who is actually paying attention to this thing, perhaps he realized that Bitcoin has proven itself and is now starting to make inroads outside the Bitcoin community.
Right, it's not necessarily a bad thing to have one entity purchase a large amount of coins. The following "source" is not really credible proof I suppose, but just by looking at the charts for the last few days, you can see that the price increases were driven by a select few gigantic purchases.