There are several key differences between this funding cycle and the .com bubble: First the bubble was marked by several businesses receiving millions or even billions without any revenue or a solid business plan. Now, most companies that receive funding are already revenue positive or have a proven business plan. In the bubble, there was trillions of dollars floating around for IPO after IPO. Now, companies are looking to venture capital for funding, and as a result of Sarbanes Oxley there isn't the avalanche of IPO's that flooded the market back then. Finally, the cost of creating a web based business has come down so much that it's possible to create a revenue positive business with less than a month's salary for a decent developer. No doubt there are a record number of deals being closed at a high valuation, but that's a side effect of the market. Having said that, if the market crashes, I'll happily eat my words but I really think the market has changed.