Organ Donation: Friends Saving Lives - Facebook users can now declare their organ donor status right on their timeline, and in the initial roll-out of the feature, some organ donor registries have seen daily spikes in new donor submissions of up to 800%.

Uber: On-Demand Mariachi Fiestas - The mobile taxi app Uber is taking advantage of Cinco de Mayo as a marketing opportunity by allowing users in San Francisco to order an on-demand fiesta, that includes a pinata, a song from a mariachi band, and a bottle of margarita mix, all delivered by an Uber van in under an hour.

Zynga’s New Ad Pitch for Draw Something: ‘Draw This Brand’ - If you were wondering how Zynga planned to make money off their $200 million purchase of Draw Something, the answer, unsurprisingly, is ads. Expect to be drawing Nike swooshes and Starbucks coffees as a regular part of your friendly competition.

Want a sneak peak at Coca-Cola’s new ‘liquid’ marketing strategy, as well as what’s worked and what hasn’t for them recently? Surprisingly, they’ve laid out the entire thing across nearly 18 minutes of YouTube video, and illustrated it to make sure you stay entertained.

Pepsi - Pepsi’s not out of the soda race just yet however, as they recently launched their now ‘Live For Now’ campaign, which transforms the pepsi.com homepage into a real-time dashboard that uses the hashtags #now and #livefornow to aggregate the ‘now moments’ from pop culture, news, events, offers and more, all ranked by social popularity. You can even dive into specific dates and locations if you want to use it as a dashboard for the social conversation at any given time or place.

This Video Has a Frightful Secret That Only Your Digital Camera Can See - A very clever campaign that uses the way that cameras capture images to spread a brand message through YouTube that remains secret unless you know how to ‘crack’ the code.

Snapguide: Simple Sharing to Pinterest - Snapguide is the first moblie app to roll out easy Pinterest integration via the new Pinterest API, allowing people to share their Snapguide guides to their Pinterest friends with a single click. This is a smart move by both platforms, as it gives Pinterest a great source of original content, and it gives Snapguide a large community to share content with.

LinkedIn to acquire SlideShare - Expect to see many more slide decks being shared by your LinkedIn connections, as the social network has just purchased the presentation tool for $120 million.

Instagram Appears To Have Passed 25 Million Users, Adding Up To 3000 More Per Hour - Instagram shows no signs of slowing down, and it appears there are now more than 25 million users, with 3,000 more signing up every hour. (And keep in mind, it’s only available on the iPhone, though they’ve said there’s an Android version in the works.)

Zynga.com - Following their IPO, Zynga has officially launched their own platform, enabling users to play outside of Facebook, and ensuring that the social game network can continue, even if Facebook makes changes that would otherwise have limited its growth.

SXSurvival - GSD&M is an agency based out of Austin, TX, so for SXSW, they decided to help incoming agency folk fit in like the locals. However, in addition to the traditional microsite, they built out a series of Pinterest boards with tips on where to eat, what to bring, and what day trips to take.

Work Club Is Looking For A New Creative Director - Work Club is looking for a new Creative Director, but instead of posting a traditional help wanted ad, they created a Pinterest board to describe their perfect candidate.

Helping Improve the Mobile Web - Among other mobile announcements, Facebook hinted at something that could have HUGE implications: They’re partnering up with most of the major mobile phone operators to enable streamlined mobile payments, allowing developers to charge for apps, and users to pay with just a few clicks. Apple has proved the power of connecting a mobile platform to an easy way to pay, so this could be the start of a new wave of paid Facebook apps.

How I Became Amazon’s Pitchman For a 55-Gallon Drum of Personal Lubricant on Facebook - Nick Bergus made a joke about a 55-gallon drum of personal lube, and a week later, found out that his picture was appearing alongside the lube in ads on the Facebook Walls of his friends and co-workers. Expect to see more stories like this pop-up as Facebook advertisers do everything than can to connect users with the products they’re trying to sell.

Reddit: The Free Internet Act - Reddit worked hard to kill SOPA, but instead of sitting back and celebrating their victory, they’re actively taking steps to try and figure out the best way to “protect copyrighted content and intellectual property holders from copyright infringement” while still preserving users’ rights.

Brad Keslowski Makes NASCAR History With First In-Vehicle Tweet & Pic During A Race - The Daytona 500 was red flagged after an accident involving a race car and 200 gallons of jet fuel, but that didn’t stop Brad Keslowski from getting out his iPhone ON THE TRACK and Tweeting out a pic of the fire from inside his car, and then responding to fans on Twitter. If you needed more proof that we now live in a hyper-connected world, this is it.

@AngiesRightLeg and @JLosNipple - If your wardrobe gets a little out of hand during a major awards show, you can now expect a fake Twitter account to pop-up within minutes. And with Angelina Jolie’s Leg getting more than 45,000 followers, there’s plenty of people out there willing to subscribe for a joke or two.

WTF QR Codes - If you’ve ever wondered, ‘Do most people really not understand how QR codes work?’, this blog is your answer.

Follow-up: Tumblr’s New Policy Against Pro-Self-Harm Blogs - Tumblr decided to shut down blogs that actively promote self-harm, and in the process, stirred up quite a debate around these issues and how they should be dealt with online. It’s something that will likely take some time for them to clarify, but it’s interesting to see them take such an active roll in an issue that’s often ignored or swept under the rug by other networks.

Fun’s Over! NBC Sics The Lawyers On The Inspector Spacetime Kickstarter Project - On NBC’s ‘Community’, the main characters watch a show called Inspector Spacetime, based on the adventures of a humanoid alien inspector who travels the galaxy in his flying phone booth. Following the episode, fan groups popped up for the non-existent show, and the actor who played the otherwise minor role of Inspector Spacetime decided to try and make an actual show out of it, funded in part through a Kickstarter program. Sadly, NBC’s lawyers came in and shut the whole thing down, but it’s an interesting example of how quickly something can go from a minor joke to a major community effort thanks to the power and speed of social media.