When Pepsi announced their plans to forgo their annual bout with Coca-Cola on the Super Bowl airwaves and instead opted for a larger social media spend, the Web went nuts. Now, with the “big game” looming ever larger in our sight lines, the actual buzz has been built up to the point where you can’t help but wonder exactly how all this is all going to shake out on the impressions and ROI end.

Alterian already dove into the metrics side of things with their study on Measuring the Effectiveness of Super Bowl Advertising Using Social Media, which looked at things like mentions and sentiment, but no one is really making any assumptions about how the plan will pay off in the end (or how many folks will be demanding a refund in some possible cases).

It might surprise some (and give others a “No crap, Ron” moment) that my background is in public relations, not social media. From a PR/messaging angle, this is genius. I can’t tell you how many of my Google reader items in the past month or so have been about Pepsi’s decision to run this campaign. For every Ad Age piece, there are 10 smaller publications running the release or quoting a larger outlet – the reach is amazing. Even friends and family who I’m fairly certain know more about how to fix a typewriter than about social media have brought the Pepsi campaign up in conversation, so maybe there’s a win in here buried under the dollar signs.

In a time where nearly 51% of people say they like the commercials more than the action on the gridiron, taking what essentially is paying for eyeballs to see your brand can seem like a bit of a leap – and it is, people (and that’s coming from someone who works in social media). However, I’m sure the minds behind this endeavor weighed the costs and benefits of such an action, just like any responsible brand would do— whether they was used their own internal monitoring and analysis or got analysis from an outside agency.

Essentially, this move will come down to three factors:

1. Staying power – How long will the buzz around the Refresh Project continue after the hype about Pepsi not running Super Bowl ads dies down?
2. Targeting – Are these social media efforts really going to fall onto the digital ears of those that Pepsi is trying to reach and, more importantly, will they get the message?
3. Goals  – Pepsi hasn’t published any goals (duh) and most of us probably don’t have any insight into exactly what sort of ROI they expect from this decision, but you can rest easily knowing that SCG (along with anyone else with an analytics department) will be crunching the numbers post-game to see what kind of comparisons we can make.

The $20 million Refresh Project comes out to the equivalent of about 7 Super Bowl ads at the estimated $3 million per 30-second spot rate that most are buying at – well below their $33 million dollar spend in 2009, so there’s some cost-cutting going on, that’s for sure. What’s still left to be decided is whether that cost savings, when added to their Super Bowl concert series and social media campaign, will equal a win for the Pepsi team.  The truth is in the numbers, and the numbers are flying out faster than a pass from Peyton Manning.

More to come here, folks— so stay tuned.