Countless variant covers, characters being killed off, people buying boxes of books and holding them on speculation. Sure sounds like the 1990s bubble to me. I have to wonder what would have happened to the market if eBay had been around back then.
eBay is the major difference between this bubble and the 1990s bubble. eBay has allowed for a much, much larger audience to have an opportunity to get at these books and, in turn, has led to fiercer competition for the books. Add in the fact that people are buying books based on movies or TV shows that may happen which sounds a lot like stock speculation, only with a physical commodity instead of a stock, bond or investable commodity like oil futures.
Deadpool is hot right now, but NM #98 is not a particularly rare book, even in high grade. There are 4,475 copies in the Census between 9.0 and 9.8. Once the speculators have paid their pretty penny for their copies, the market will correct itself and prices will stabilize. As a collector and a Deadpool fan, I'd be insane to pay market prices for a 9.8 copy of NM#98 right now.