The three most talked about Super Bowl advertisers on Twitter were McDonalds, Always and Budweiser

"From the coin toss to the post-game wrap up, #SB49 saw advertisers bring their creative firepower to Twitter as they looked to drive conversations during yesterday’s thrilling game between the @Patriots and the @Seahawks.
For the last three years, we ran #AdScrimmage to celebrate the in-game commercial that garnered the most votes via Tweets. This year, in order to better reflect the true nature of the brand conversations on Twitter, we broadened the definition of “vote” to include brand, commercial and other related mentions, starting from the coin toss to when the clock hits 0:00 (the live window). This more accurately reflects which advertiser saw the most conversation on Twitter. We’re calling the victor this year’s #TopSpot.
We’re excited to announce that McDonalds (@McDonalds) is the winner of this inaugural #TopSpot competition, gathering 634,310 mentions during the live window of the game.
Always (@Always), with 455,695 mentions and Budweiser (@Budweiser) with 371,900 mentions during the live window, rounded out the top three most-talked-about brands on Twitter during the game.
[...]
Measurement of the #TopSpot included mentions of the brand and/or the commercial. Organic conversation that counts toward this measurement consists of the number of original Tweets mentioning a brand advertising spot in a variety of forms, including:
mentions of brand name
brand Twitter account
product name
hashtag included in commercial
subject matter of commercial
mentions of celebrities appearing in commercial"

Source:  Twitter's Advertising Blog, 2nd February 2015