Digital advertising technology company SocialVibe today announced a $20 million round of funding led by investor Norwest Venture Partners. The company plans to use the money on global expansion of its brand engagement advertising strategy.

SocialVibe has been a long-time advertiser partner for Zynga, running its ads as part of the offer walls in games like PetVille and CafeWorld. Like many other offer wall advertisers, users earn virtual currency in these games by watching a video, completing a survey or otherwise participating in a branded promotion; but SocialVibe distinguished itself with high-quality advertising, plain, easy-to-follow instructions and quick turnaround time on redeeming participation for virtual currency. Clearly, the approach worked as Zynga’s offer walls now offer dozens of advertisers instead of just the four we noted in PetVille last year.

SocialVibe has been expanding to interactive ads that reward participants with a sense of play or accomplishment. We’ve covered its Thanksgiving ad engagement Facebook app that drew in users by offering charitable donations to the United Nations World Food Programme in exchange for filling a virtual table with virtual food; the company has offered a range of similar types of ads, notably the Kia Motors engagement app that SocialVibe ran during Super Bowl XLV in February.

The Kia app allows players to pit one Zynga game against another in a mini-Super Bowl experience. Players select a Zynga game character set to form their team (e.g. FrontierVille’s avatars against the pets of PetVille) and one of three plays to run toward a touchdown in seven-second animations. A “halftime show” by Kia Motors presents players with a three-question survey and then returns them to the “game” portion for the second half.

The entire activity takes a little over a minute; SocialVibe claims that its engagements average around 63 seconds with an 80% completion rate. Of those totals, the company says, 41 percent click through to a Page or website, 30 percent show purchase intent, and 15 percent share the experience with friends for a viral effect.

In addition to Norwest Venture Partners’ participation in the round, SocialVibe also secured participation from existing investors Redpoint Ventures, Jafco Ventures and Pinnacle Ventures. Jeff Crowe of Norwest Venture Partners now sits on SocialVibe’s Board of Directors.