This holiday season, Gap’s multi-platform marketing efforts include a key influencer program that features actors, models, bloggers and even the co-founders of Foursquare. Each influencer has selected a charitable organization to support – and for each person who Likes one of their embedded YouTube videos, US$1 will be donated to their charities of choice. Additionally, there are special deals hidden throughout the brand’s Facebook page – many of which can be redeemed in stores (e.g. say “Viral 30″ at the cashier to receive 30% off one regularly priced item).

Not only are Foursquare co-founders Dennis Crowley and Naveen Selvadurai included as two of the key influencers (appearing in print ads and online promotional efforts), GAP has also partnered with the popular location-based service in their new interactive banner ads. According to Mashable, the ads will push to the latest fashions and in-store deals with special “Add to Foursquare” buttons. These buttons will add Gap’s nearby Foursquare tips as a To-Do action item on the user’s Foursquare account and provide them with a 30% discount. The banner ads are geo-targeted, so the Foursquare tips will apply to actual store locations within the user’s immediate vicinity.

Almost thirty years ago, the chief economist at PNC Bank was inspired by the song The Twelve Days of Christmas – going as far as creating a price index to calculate how much each item mentioned in the Christmas song would cost if it was purchased then. This unintentional tradition has become a celebrated part of PNC’s holiday calendar.

The PNC Christmas Price Index now exists online – with all 78 whimsical gifts and services priced and added up to determine the “total cost of Christmas”. Users are able to browse through the items to see how much prices have changed in the past year, and explore a beautifully designed microsite that is set up to look like a children’s pop-up book.

The new issue of Wired magazine for the iPad features a hidden video trailer. The graphic content is of two people discovering the body of a lifeless creature on the side of an unidentified road. It is mysterious and disturbing – upon first glance, the viewer is not provided with any context around the clip.

It has since been revealed that the teaser may be for an upcoming film by Academy Award-nominated writer and director Neill Blomkamp, who was behind 2009′s District 9. The aesthetic and camerawork are very similar, and the execution of this trailer as a hidden nugget in Wired’s iPad app have created tremendous buzz online. The secrecy has only worked to the potential film’s advantage, as film enthusiasts take to the web to dissect each frame and discuss what the movie might be about. Additionally, users are uploading the video to their own personal social channels (including Facebook and YouTube), to spread the word amongst their own personal networks.

In Spain, one of Jeep’s new advertising campaigns uses Twitter in an ambitious effort to engage brand enthusiasts online. Fans are encouraged to unscramble 371 Twitter profile pictures to create images of various landscapes which embody the Jeep lifestyle. These puzzles are to be completed on Twitter.com, where each Twitter user’s contacts are featured on the right side of the interface. Once these puzzles have been solved, the users include #jeeppuzzle in a Twitter post, notifying @JeepPuzzle of their completion for the chance to win a variety of prizes.

We find the creative concept interesting, but unfortunately it does not work on New Twitter’s interface.

Sesame Street’s marketing team has turned to the social web for its newest stunt — encouraging fans to support their bid to have Cookie Monster host Saturday Night Live in New York. This is not the first time that the Sesame Street team has leveraged their social channels (most recently, Elmo was seen in an Old Spice parody called Smell Like a Monster on YouTube). It is also not the first time that the popular children’s program has been tied with SNL. During its first season, Sesame Street creator Jim Henson developed stories and characters for the show.

Cookie Monster’s attempts to get on SNL focus around a YouTube video, where he plays out popular skits from the television program (e.g. MacGruber). He even goes as far to create a campaign-specific Facebook page that now boasts 57,957 fans. This is in addition to the 835,904 fans that Cookie Monster has on his main Page.

In anticipation for the holiday shopping season, Amazon has launched a free new iPhone Price Check app catered to provide its users with the best possible deals. It will scour nearby offers both from Amazon.com as well as other online merchants. Users can search for the most competitive prices on a variety of products (including books, DVDs, CDs and video games), simply by doing one of the following:

- Scan barcode of product
- Take photo of product
- Speak or type in name of product

American electronic pop band Au Revoir Simone released their newest song, Knight of Wands earlier this month. With it comes an interactive website that allows fans to recreate an illustrated version of the music video with a paint-by-numbers digital palette. This microsite is built in Flash, and also features the actual video.

The illustration includes numerous hidden ‘Easter eggs’ to serve as incentive for fans to create and share more than one version of their artwork. Once users are finished, they are given the option to share their final pieces through social channels such as Twitter, Facebook and Flickr.

German site Freunde von Freunden (which translates into ‘friends of friends’) is an online magazine that features interviews with creative personalities in Berlin and the surrounding area. It is a miniature social network in itself, with the interviewees and members of the community nominating the next candidate through what appears to be an informal referral system. With the overwhelming growth of popular channels such as Twitter and Facebook, it is interesting to take note of smaller-scale sites such as this and the recently launched Path – which both promote more niche/personal communities with in-depth interaction.

The Freunde von Freunden interviews are primarily in German, and feature photo/video content of the individuals in their personal work and living spaces. From loft studios to dining rooms, Ailine Liefeld captures an intimate glimpse into each interviewee’s day-to-day influences. The site’s concept and aesthetic is very similar to that of The Selby — in addition, Freunde von Freunden also boats a strong presence on various social channels such as Tumblr, Facebook and Twitter.