In this age of social media, some questions have perplexed marketers: What's a tweet worth? What's a share worth? What's a hashtag worth?

Starting today and continuing through Dec. 1, the answer will be clear, at least to Durex, billed "the Global Sexual Wellbeing giant" by its corporate overlord Reckitt Benckiser, also marketer of Bang, Finish, Vanish and Suboxone. Each tweet bearing the #1share1condom hashtag and each share of the World AIDS Day image or video found on Durex USA's Facebook page will be worth precisely one unused condom.

Durex will donate the condoms to global and local charities dedicated to preventing the spread of HIV, limited only by the degree to which people share the love in social media and a 2.5-million-unit cap on its prophylactic philanthropy. That equals the 2.5 million people newly infected with AIDS in 2011, according to UNAIDS.

Even if you consider the 144-count value-priced variety-pack sold at Walmart.com, that adds up to more than $600,000 worth of condoms at retail, or around 24 cents per tweet.

"We've supported the fight against HIV over the years, mainly through local projects," said Kevin Harshaw, marketing director of personal care at Reckitt Benckiser, in a statement. "This year, we have decided to use our global market presence to create an initiative that will get the world talking and sharing."

Additional information can be found at 1share1condom.com.