Those of us who lived in San Francisco at the turn of the millennium remember the dot com bubble and what followed with grim nostalgia. (Kozmo! Roof parties! Everybody IPO! Layoffs! Wondering if you will have to move back in with your parents!) That might be one of the reasons some of us talk about the current age of local prosperity as a "bubble." It's not that we necessarily want it to pop, it's that we remember what happened — not just to tech workers — last time, and we don't want to go through that again. So, when a tech-investing billionaire who managed to emerge unscathed from the bust of 2000 starts making grim, bubbly, predictions, should we freak out?

Mark Cuban is, according to Forbes, worth $3 billion, an empire he built after "selling video portal to Yahoo for $5.7 billion in 1999, cashing out just before the tech bubble popped." He's also on Shark Tank, that show where people pitch their company/invention to a panel of rich folks who may or may not want to invest. In a blog post this week, the investor took a decidedly skeptical look at the current state of business affairs, saying that "If we thought it was stupid to invest in public internet websites that had no chance of succeeding back then, it’s worse today."

In a bubble there is always someone with a “great” idea pitching an investor the dream of a billion dollar payout with a comparison to an existing success story. In the tech bubble it was, AOL, Netscape, etc. Today its, Uber, Twitter, Facebook, etc.

To the investor, its the hope of a huge payout. But there is one critical difference. Back then the companies the general public was investing in were public companies. They may have been horrible companies, but being public meant that investors had liquidity to sell their stocks.

The bubble today comes from private investors who are investing in apps and small tech companies....I have absolutely not doubt in my mind that most of these individual Angels and crowd funders are currently under water in their investments. Absolutely none. I say most. The percentage could be higher

Why ?

Because there is ZERO liquidity for any of those investments. None. Zero. Zip....So why is this bubble far worse than the tech bubble of 2000 ?

Because the only thing worse than a market with collapsing valuations is a market with no valuations and no liquidity.

You can read his entire post here.

But is he right? Not according to Silicon Valley Business Journal Senior Technology Reporter Cromwell Schubarth, who says that Cuban's bubble hypothesis is full of leaks.

Cuban "appears to make an apples and oranges comparison between what is happening today and what happened back in 1990s," Schubarth writes, saying that "Main Street investors aren't directly at risk if the likes of Uber, Airbnb, Dropbox or Palantir Technologies collapse."

In fact, regarding Cuban's arguments that most app investors are underwater, Schubarth scolds "That would be typical of investing in startups, not an exception. The average failure rate for angels and VCs is greater than 90 percent."

But even Schubarth's dismissal of Cuban's points still suggests things can't continue as they have, saying "that doesn't mean we aren't in a bubble, of course. Many from the venture and angel world say that they believe we probably are."

"The unresolved question, Schubarth writes, "is how this one will pop, with one big burst or a bunch of smaller pops." Oh, you mean like these?