The price of bitcoins has plummeted over recent days and the largest exchange for selling the virtual currency was also apparently hit with a strong distributed denial of service (DDoS) attack.

MT Gox Exchange was forced to go offline, apparently more than once, but the reason for the lapse may be either the DDoS attack or the trading firm upgrading its service to handle increased volume – or both.

One lapse lasted 12 hours on Thursday so the exchange could improve its infrastructure, The Telegraph newspaper reported. Then last night there was another apparent lapse.

“We are experiencing a stronger than usual DDoS. We are working in it.” MT Gox said in a Google (News - Alert) Plus statement that was issued early Friday morning.  

Trading resumed, and as of 10:15 a.m. (ET) Friday, MT Gox was selling bitcoins for $79. By 11:09 a.m., they were selling for $69.04.

The news media has focused its attention to the ups and downs of the digital currency.

“The price of Bitcoin has imploded, falling from $266 on Wednesday to roughly $55 on Thursday,” said a report from CBS News. The report also quoted Nicholas Colas, chief market strategist for the ConvergEx Group, who claimed it was a "great question" whether bitcoins will survive these kinds of swings.

"Its trading is typical of a bubble," Societe Generale analyst Sebastien Galy told CNN Money in a statement. "But there are still people who believe in it. You can't say we're going to zero tomorrow. Even assets that have no underlying value have people willing to trade in it."

During Thursday morning, trading was halted on MT Gox not because of a hacking attack, but because it was a “victim of our own success,” the company claimed in an online statement issued on April 11.

“Indeed the rather astonishing amount of new account[s] opened in the last few days added to the existing one[s] plus the number of trade[s] made a huge impact on the overall system that started to lag,” the company added in the statement. “As expected in such [a] situation people started to panic, started to sell Bitcoin in mass (Panic Sale) resulting in an increase of trade that ultimately froze the trade engine!”

MT Gox said on April 11 that the number of trades executed “tripled” in 24 hours. The number of new accounts opened went from 60,000 for all of March to 75,000 for the first few days of April.

“Due to these facts we have been busy working on improving things since last week and our team has been working around the clock to improve Mt.Gox to catch up with the demand. We will continue to release several updates today and in the coming few days to improve our system overall performance.  Also please note that we may have to close the exchange for two hours in the next 12 to 24hrs to add several new servers to our system,” the Thursday statement added.

MT Gox is responsible for some three-quarters of the trades in the digital currency.

Bitcoins are being watched carefully as an option, with some investors wanting to avoid financial problems in Europe, such as in Cyprus, and others just seeing them as an investment which makes sense. Increasingly, retailers are willing to accept bitcoins for payment.

Hackers have also targeted the currency. The bitcoin's value fell $30 in a single day last week after a DDoS attack against MT Gox. MT Gox said the DDoS attack may have been caused by those who want to see bitcoin trading destabilized.

“Mt.Gox is an easy target for anyone that wants to hurt Bitcoin in general,” the company said in a statement quoted last week by TMCnet. Another possible motive was to “abuse the system for profit. Attackers wait until the price of Bitcoins reaches a certain value, sell, destabilize the exchange, wait for everybody to panic-sell their Bitcoins, wait for the price to drop to a certain amount, then stop the attack and start buying as much as they can. Repeat this two or three times like we saw over the past few days and they profit.”

Just as there is speculation that the bitcoin bubble has burst, Cameron and Tyler Winklevoss, the brothers who sued Facebook (News - Alert) founder Mark Zuckerberg for stealing the idea for Facebook from them, may have had up to $11 million invested in bitcoins. That estimate came when bitcoins were selling for $120 each and they owned some 92,000 bitcoins, according to news reports.

Cameron Winklevoss told The New York Times, “At some point that narrative will shift to ‘virtual currencies are here to stay.’ We’re in the early days.”

“We have elected to put our money and faith in a mathematical framework that is free of politics and human error,” added Tyler Winklevoss.

Meanwhile, their investments led PC Magazine to ask the enticing question in a recent headline: “Are the Winklevoss Twins Trying to Corner the Bitcoin Market?”