Our online video habit is rapidly becoming a pastime, with new research showing that the average online viewer spent more than 13 hours a month viewing online videos in May. Does this hail the end for TV and ultimate domination for YouTube and Hulu?

According to the latest ComScore research, the average online video viewer watched 186 videos in May, with the average video being 4.3 minutes long. That comes out to 13.3 hours on average per viewer per month, and a year-on-year growth rate of 75%. These are no small numbers.

But considering TV viewing hours statistics reported by Nielsen in March, its clear that online video streaming has a long way to go before TV programming execs need worry. According to the report, Americans spent 37 hours on average a week watching TV, or 148 hours a month, almost the equivalent of another full-time job.

TV is the clear winner, right? Not so fast.

The report also noted that 59% of Americans used the internet while watching TV, in many cases streaming video and sharing with their friends. As we reported last month,TV and social media are actually complimenting each other and increasing participation in both, a rare digital-saves-traditional-media story. Essentially, people are watching their favorite shows on TV and talking about it online at the same time. And, if they miss an episode or want to discuss an important scene they watch it online and share with others in the comment section.

Interestingly, the comScore report was quick to note that online video ad networks such as Tremor Media and ScanScout Network in the US are growing impressively, alongside the surging market. The advertisers that exploit this growth spurt will be those that find a way to bridge the gap between the two, taking advantage of the fact that people use both to augment what one channel couldn’t do alone.