The fact that Veoh’s entire site went down because of what its founder believed was a denial-of-service attack — while I was interviewing him — could be taken as a sign that the site’s massive growth over the past year is real.

I had called to follow up on Veoh’s recent announcement that its network traffic jumped 760 percent over the past year, rising to 21.5 million unique monthly viewers in November from just 2.5 million in December 2006. Veoh’s traffic represents people watching content through the Veoh network, including Veoh.com, Veoh TV and embedded players. The company counts a view as soon as the player starts, and doesn’t count it again if it’s re-started in the same hour. Veoh went on to say that 30 million hours of content were consumed through its network for the month of November, and that the average viewer consumers more than 80 minutes per month.

All that traffic does make it a nice, juicy target for a denial of service attack. Which is what Dmitry Shaprio, Veoh’s founder and chief innovation officer, speculated as the site went down during my interview with him today. “It started at 11 a.m. today,” said Shapiro, referring to a spike in traffic. “We saw giant increases, three to four times the amount of traffic. It looks like traffic that may be automated.” I wonder what happened to his calm demeanor after we got off the phone, as the outage itself lasted from roughly 2:30 p.m. PST until 4:00 p.m. PST.

In addition to its site and embed traffic, Veoh reported that its downloadable VeohTV client has been installed by new users 1.8 million times over the last two months. VeohTV beta was launched in June, but the company would not reveal the total number of installs for the service. According to the company, users are spending an average of 19 minutes on VeohTV, but did not have specific data on the type of programs that people were watching.

When speculating on the steady increase in traffic over the past year, Shapiro said “Over 99 percent of our traffic is completely organic, through word-of-mouth, search engines, embedding. It’s not paid. We’re not buying this traffic.”

Veoh has also had a problem with spam in its comments section lately, with nefarious solicitations for pirated movie-streaming and anime porn topping the comments in some of the top videos of the week. Maybe the company should take that money it’s not paying for traffic and put it into network security.