“Election Day 2008’s tweet volume represents only about six minutes of Tweets today.”

If you read that and said “Wow,” join the club. If people thought that 2008 was the big “social media election” based on Barack Obama’s reliance of Facebook and Twitter to mobilize support – they obviously have no idea how huge of a role it’s playing in 2012. The top social networks have grown exponentially in the last four years, as has the resources political candidates have to use in promoting and maintaing a strong presence.

And there are simply a massive amount of tweets going out everyday. Twitter says that more tweets are sent every two days than all of the tweets before 2008 combined. And with that in mind, Twitter has decided to use that massive source of real-time data to build their own public opinion meter.

With the help of analytics company Topsy and polling firms Mellman Group & North Star Opinion Research, Twitter has unveiled the Twitter Political Index.

The Index judges the sentiment in tweets that mention Romney or Obama, and gives each candidate a number based on how positive their mentions are in relation to 400 million other tweets across the network.

From the Twitter blog:

Each day, the Index evaluates and weighs the sentiment of Tweets mentioning Obama or Romney relative to the more than 400 million Tweets sent on all other topics. For example, a score of 73 for a candidate indicates that Tweets containing their name or account name are on average more positive than 73 percent of all Tweets.

The Index is located at election.Twitter.com. Here’s what today’s index looks like:

As you can see, the Index also shows the +/- change from the previous day. The Twitter Political Index updates every day after 8 pm EST, in order to properly reflect all of the conversation across Twitter for the day.

The Index page also include an interactive graph of changes in the Political Index over time:

Political junkies who want to follow public opinion on the two candidates until November can just visit the Index page. Or they can follow @gov for occasional updates. Twitter says that USA Today will be integrating their Twitter Political Index into their coverage of the campaign as well.