This Sunday is the Super Bowl, and over at CNBC Julia Boorstin previews what the big game will mean for Twitter:

Twitter is expecting thousands of tweets-per-second, making it one of its biggest events ever. Tweets have become such a powerful tool for advertisers that Nielsen, which last year announced a partnership with Twitter, is releasing a new metric to show the value of the “second screen.”

Here’s an amazing statistic: a Nielsen study revealed that a third of people using Twitter are tweeting about content they’re watching. And Twitter found that 65 percent of people are accessing Twitter via mobile devices while watching television.

Interestingly, Boorstin reports half of the commercials airing during the game will feature Twitter hashtags. Two years ago, only one ad employed a hashtag.