Facebook is about to top a dubious list as the biggest-ever Internet initial public offering. Dubious, because for long-term investors the names on the list have been duds more often than not.

There's previous No. 1 World Online, along with other busts such as T-Online, Thus PLC, and Wanadoo SA. Wait, you say, those are from the Internet bubble. No fair! But even post-bubble IPOs have a mixed record. Here's a look at the six biggest in the world -- pre-Facebook.

According to rankings provided by Thomson Reuters, the largest IPO in the pre-Facebook era was that of World Online BV. World Online raised $2.7-billion (U.S.) in a 2000 IPO. The stock debuted on the Amsterdam exchange at €43 a share. The deal immediately proved a bad one, as by the second trading day the stock was well below its listing price. Only months later World Online merged withTiscali, an Italian company, in an all stock deal valued at €15.35 a share. Today, Tiscali has a market cap of €67-million.

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Next on the list is T-Online International AG, the internet arm of Deutsche Telekom. T-Online hit the market at €27 per share in 2000, raising $2.7-billion (U.S.) for the selling shareholder. Four years later, Deutsche Telekom bought the last of the stake back, offering €8.99 in cash.

In the third spot is Thus PLC, another Internet provider which came to market in London in 1999 and raised almost $2-billion. The IPO price was £3.10. Cable & Wireless PLC bought Thus in 2008 for £1.80.

Finally, at No. 4 in the pre-Facebook era, there's a winner. That, of course, is the IPO of Google Inc. in 2004 at at $85 a share. 'Nuff said.

Back to the bad news in the No. 5 spot. Wanadoo SA went public in 2000 on the Paris market at 19 euros a share. Like some of the other big flops, the company's claim to fame is that it was an internet provider. The company was taken over in 2004 for €8.86 a share.

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Next is a wonder of Asian Internet hype. In 2007, Alibaba.com Ltd. went public on the Hong Kong exchange. The buzz was Facebook like, and there were orders for 180 times more stock than was on offer. The stock rocketed higher from the IPO price of $13.50 (Hong Kong), handing investors a near triple in the first day. Alas, it didn't last. The company now trades at $8.75 a share.