Looking at the just-completed Super Bowl, we may have our answer: a kind of retro solution -- QR codes appearing onscreen during a TV commercial. Point your handy mobile phone and take a picture. That’s it. You're in.

But as Coinbase Global found out, some TV advertisers may not be ready for this.

Traffic to the cryptocurrency exchange company crashed the app during its Super Bowl commercial airing. Why? The QR code -laden commercial came with a high-profile promotion -- $15 worth of free Bitcoin for new sign-ups.

Multitasking in front of the TV screen is growing. Coupling this with free stuff could offer instant gratification to TV viewers.

And consider that all this activity comes amidst the biggest sports event of the year, with the additional hyped-up business of sports betting via more related TV commercial advertising.

Many newfangled stock-market investment tools could be equated to gambling for some. Factor in some heavy partying from viewers -- alcohol-inspired -- and you have the making of a good promotion.

Not sure if this would work for the likes of a Procter & Gamble, perhaps with a QR code as part of a commercial. The consumer products giant could offer up free giveaways of Charmin and Crest mouthwash. But is that enough?

QR codes also might go hand in hand with the immediacy of live TV. So there are sports and -- yes, TV news networks.

CNBC has been touting its "CNBC Investing Club" with Jim Cramer for some time with a promotional spot attached with QR code. When scanned, it takes viewers to web areas of deep investing insights from Cramer, including videos and other content.

Live TV content is already a strong media opportunity for marketers these days in a world of exploding content.

But adding another connection -- a direct, immediate and hands-on -- could be a good thing.

Taking it a step further, should big brand advertisers act more like direct-response advertisers?