Two seconds. That’s when Internet users start ditching online videos if they’re not loading properly, according to a new study from the University of Massachusetts Amherst and Akamai Technologies. By the 10-second mark, if the video still hasn’t loaded, about 40% of Web users will have abandoned it, according to data presented in the study. On average, for every second that the video doesn’t start playing after the two-second mark, there’s a 5.8% increase in the rate at which the video viewers bail. The findings vary depending on the video. “Viewers are less tolerant to startup delay for a short video such as a news clip than a long video such an hour-long TV episode,” the authors say. But, in general, the findings seem to confirm a truism in the twitchy world of the Internet: Online users don’t like to wait. “The study … contains no startling surprises – most of us probably suspected that people give up on watching videos that don’t load,” Jeff John Roberts writes on the site GigaOm. “But it does provide useful empirical evidence for companies who must decide how to invest architecture to support their video platforms.” Some technology bloggers were surprised people didn’t click away from glitchy videos faster. And previous reports, including one from the New York Times, suggest Web users are even more impatient when it comes to text-based Web pages. The Times in February cited Harry Shum, from Microsoft, as saying that people will go to a website less frequently if it loads 250 milliseconds slower than a competitor’s. As this graphic highlights, that’s faster than the blink of an eye. “Every millisecond matters,” a Google engineer told the paper. The UMass-Amherst paper was based on data collected from 6.7 million unique video viewers over a 10-day period, according to the report. The test subjects played a total of 23 million video views. The study finds video quality has a potentially longtime impact on a website’s popularity. A “viewer who experienced failure” is about 2% less likely to come back to that same site that week, compared to a person whose videos loaded smoothly. Finally, the video-loading game seems to be one of expectations. People who are trying to watch videos on a mobile phone are likely to be a bit more patient than those on desktop computers with high-speed connections. It’s easy to see how that would be the case. Think back to the hee-hawing days of dial-up Internet and remember how long you used to wait for a single photo to load on a super-slow Internet connection. In part because of this, Dante D’Orazio writes for The Verge that efforts to make online video load faster and faster may amount to an “unwinnable battle.” “There may very well be a point when we’ll no longer notice,” he writes, “but for now, it seems that you can never have enough speed.” Hate online wait times? Have thoughts on the report? Take two seconds and let us know what you think of all this in the comments section.