I think the huge valuation isn't about what LinkedIn represents today, it's a gamble on what LinkedIn could mean in the future. Amassing a huge network of corporate data across myriad industries and you do for salespeople what internet did for porn. If it permeates the culture like Facebook has done, it could become the way everyone gets hired in the future. http://youtu.be/9n-eNpoHgS8

A lot of people are talking bubble on this one. We have seen it time and again. While LinkedIn may be somewhat overvalued at $9 billion, the true bubble out there right now is Groupon. I have had hands on experience with Groupon reps, and behind that "too cool for school" facade there is a lot of pressure by Groupon to have businesses overstate the value of what is being offered, just so Groupon can hit the 55 percent discount mark. People are going to catch on, the market for online deal sites is already fracturing at an alarming rate, as is evident by the YADDS phenomenon. It will be really interesting to see what the Zynga IPO does, because it is not a household name for many and therefore might offer some sort of yardstick by which to measure Groupon and Twitter when they eventually go public. On a side note, winning at Chess with Friends makes me happy. Losing at Chess with Friends makes me depressed. http://youtu.be/9n-eNpoHgS8