social media: youtube as a case. 2 new generation of video sharing service feb.15th, 2005 some...

Social Media: YouTube as a CaseSocial Media: YouTube as a Case

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• New generation of video sharing service• Feb.15th, 2005• Some statistics:

• 60 hours video uploaded very minute • 4 billion views daily (Jan 2012)

• 14 billion videos viewed (May 2010)

• 20% growth per month• 3rd most visited site (behind Google and Facebook)

• 43% market share

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BackgroundBackground

• Web 2.0 and UGC• Web 2.0

• Facebook, Flickr, Google Map, etc.

• User Generated Content• Communities, Social network

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YouTube ChallengesYouTube Challenges

• Client/Server architecture• Bandwidth costs

• 20% of all HTTP traffic, 10% of all traffic on the Internet• Traffic Cost: $11 million per month (assume $10 per Mbps)• Sold to Google for $1.65 billion on Nov.13th, 2006

• Scalability and performance• “Slow, 69% other are faster” (Alexa.com)

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• YouTube Meta-Data

Are YouTube videos different from traditional videos?Are YouTube videos different from traditional videos?

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Statistics of YouTube VideosStatistics of YouTube Videos

• Video Category• Highly skewed

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• Date Added• Increasing steeply

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• Video Length• Most distinguished• Short video clips

• 97.9% ≤ 600s, 99.1% ≤ 700s• Due to the 10 minutes limit

• Now 15 mins

• Unlimited for power users

• Three peaks

• Different from traditional videos• 1-2 hour movies

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• Video File Size• 98.3% less than 25 MB• average 8.4 MB• Millions of videos !

• Video Bitrate• Most around 330 kbps

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YouTube Video FormatYouTube Video Format• Initially, 320x240 pixels, Sorenson Spark codec (H.263),with mono MP3 audio• June 2007, 3GP format on mobile phones• March 2008, 480x360• November 2008, 720p HD,

4:3 aspect ratio to a widescreen 16:9H.264/MPEG-4 AVC

• November 2009, 1080p HD • July 2010, 4K format: 4096x3072

YouTube accepts upload in most container formats and performs conversion

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• Views• Long-tail• Does not fit Zipf’s

• Not so many unpopular videos (i.e., views fewer than 100)

• Gamma, Weibull• Zipf’s

• Website access

• VoD

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• Ratings and comments• Still, users are more willing to watch videos rather than

to log in to rate and make comments

• User Friends• Average: 4.3, Median: 0• 58% no friends

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Social Network of YouTube VideosSocial Network of YouTube Videos

• Videos are no longer independent

• Small-World Phenomenon• Refer to the principle that people are linked to all

others by short chains of acquaintances (AKA. six degrees of separation)

• Clustering coefficient• Much larger than that of a random graph with the same

number of vertices and average number of edges per vertex

• Characteristic path length• Almost as small as that for the corresponding random graph

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• Small-World in YouTube• Strong small-world characteristics

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• Implication for Caching and Storage• Correlation between videos

• A user is likely to watch another video in the group after finishing the first one

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