Are we in a new Internet bubble? And will it burst, like the last one?

More to the point, when will it burst?

Consider the fact that LinkedIn just raised its IPO pricing by 30 percent.

And consider recent remarks by Alan Patricof of Greycroft Partners characterizing the current rush to invest in fledgling web companies as evidence of "a period of irrational exuberance," according to Reuters . As a pioneer in the area of web and technology investing, he should know.

Basically out of the park valuations for a handful of well-publicized companies--Facebook, Twitter, et al--are raising the bar too high and creating unrealistic expectations for the industry as a whole.

And it's creating a stampede of VCs trying to invest in what could be the next Groupon. From January to April, 2011, more than $5 billion of VC money was invested in such companies, according to Thomson Reuters Deals Intelligence data. This year could see the most money invested in this type of company since 2000.

Of course we all know what happened to the market at that point.

According to Patricof, the current crop of startups aren't IPO-bound, however. While every company in his portfolio was after an IPO during the first Internet bubble, none of the 45 firms he has now are interested in that as their exit strategy.

Which brings us back to LinkedIn and its IPO. That could be a taste of future IPOs for Facebook, Groupon and the other companies that have helped fuel the current VC rush to invest in the sector. Unless the current bubble bursts before they take place.