With 6.8 million Twitter followers and 9.7 million Facebook fans, Ashton Kutcher has a lot of clout in the world of social media.  He is an investor in the iPad news-reading app Flipboard, Skype (which was recently sold to Microsoft for $8.5 billion), Foursquare, and the Path photo-sharing app.

Now, the new Two and a Half Men star is becoming the strategic advisor to the travel startup airbnb.com.

For many, Ashton Kutcher is an actor and heart throb, but in the tech scene, he's made his mark as a branding and new media expert with an eye for great ideas and a fearless approach to new markets, Airbnb said in a May 25th blog post. With his incredible wit and personality, Ashton Kutcher has shown the world the power social media has on emerging brands and in developing strong, passionate communities. With Ashton on board, we'll be working together to take our community engagement to the next level and expand our international presence to reach more people from different cultures all over the world.

Airbnb is a community marketplace for unique spaces that aids budget-conscious travelers in finding lodging anywhere from an apartment to a houseboat to a castle.  It's a cross between backpacker staple couchsurfing.org and more traditional hotel-finding websites.  The site allows participants to become hosts and make money by renting out their place, be it a city apartment, a country lodge, or anything in between.

Travelers then book online, pay through PayPal, and contact the host directly to confirm check-in details.  Meanwhile, Airbnb provides 24-hour support across the globe.  After departing, travelers are encouraged to share their experiences by leaving a review and thus further validating the owner of the accommodation.

Airbnb has become the sleeper hit of the startup world. It's one of those companies that many well-heeled investors passed on in the early days because they thought that no one would want to open his or her home to strangers.

The San Francisco-based company claims listings in over 8,000 cities and 166 countries that range from private apartments to private islands.