YouTube streams 4 billion online videos each day, more than one for every other person on Earth and a 25% jump over eight months ago.

YouTube, a unit of Google, attributed the growth to iterations of the website on smartphones and TVs that have encouraged more use, according to Reuters. The number of uploads on the platform is also staggering: about 60 hours of video is now added to the site every minute, compared to 48 hours a minute in May.

It's unclear how much Google is benefiting by such growth. In its fourth-quarter earnings call with analysts last week, Google didn't break out revenue figures for YouTube. However, the company disclosed that its display ads are generating $5 billion in revenue on an annualized run rate basis. Despite that encouraging sign of growth for Google — such advertising was only a $2.5 billion business in October 2010 — Google's stock price fell 9.2% on Jan. 19, the day it disclosed those earnings.

One avenue Google is pursuing to monetize YouTube is a $100 million program featuring celebrity channels from the likes of Ashton Kutcher, Amy Poehler and Shaquille O'Neal. YouTube announced those channels last October. Many of them are expected to go live this year.

The program illustrates a problem that YouTube is trying to address. As outlined in a New Yorker article last week, despite impressive stats such as the 4 billion figure, the average YouTuber spends 15 minutes each day viewing videos on the site, but the average American spends four or five hours watching TV every day. "If YouTube could get people to stay on the site longer, it could sell more advertising, and raise the rates it charges advertisers for each thousand views," the article states, adding that U.S. advertisers still spend about $60 billion a year on TV commercials compared to only $3 billion for online video.

Want to know how to discover the best videos? Check out our tips below.

5 Fun Ways to Find New Videos on YouTube

Thumbnail image courtesy of Flickr, Rego – d4u.hu