Stefanie Michaels: Twitter has changed my life in so many ways. In just two months, I went from a travel expert for the media, to "suggested user" and Top 100 Global Twitterer. It has made me easy to find and has opened doors for me -- one very special door in particular: Operation Smile.

One morning, I was "twittering" when a direct message came in from @operationsmile. Would I work with them? In that instant, my life was changed.

Operation Smile is an International Children's medical charity that gives underprivileged children with facial deformities, such as cleft lips and palates, life-changing surgeries. I watched their videos and wept. Unbeknownst to Operation Smile, their inquiry had hit close to home. It had been years since I had addressed a family secret that had devastated my parents, and made me question whether or not to have children.

My brother, Christopher, had been born with a facial deformity. It was then called a "hair lip," with a great stigma attached. My mom would cover his face with a blanket when she would leave the house, so no one could see he was disfigured. At the time, there were no "support groups" or places for my parents to turn to, gather information, and reach out.

In addition to his cleft lip, Christopher had also been born with a brain malformation, which ultimately killed him at 6 months of age. Devastated, my parents dealt with grief differently. Mom crumbled. My dad became angry, turning away from everyone. They destroyed his photos. They grieved privately, and never spoke of him.

I was born years later, and throughout my childhood, there were clues about this mystery brother. On every August 19th, the day of Chris's birthday, my mom would hide away and cry. I always wondered what Mommy was crying about, yet my questions went unanswered.

I eventually approached my mother's sister, having heard things, names, whispers that confused me. I was 11 years old when I finally learned the truth. My aunt told me everything, how Christopher was born, that he was deformed, how he died, where he was buried, how hard it was on my parents. I learned about the fighting, the blame, the sadness, and then how I came along and saved them, made them smile again.

I honed in on the word "deformed." I pushed for more answers -- what did she mean? What did he look like? She then brought out Christopher's photos she had kept all those years. He was just this tiny baby with a "tear" in his lip. He looked just like a normal baby -- not a monster, as I first imagined. This was my brother.

I never spoke of this to any of my friends until now. I don't know why. Maybe I felt that I was honoring my parents' wishes, that it was just too painful to speak of. In fact, now that I have come forward, lifelong friends are shocked that they never knew of Christopher. I had kept my family's secret.

I am now committed to help spread the word about the work Operation Smile does. For as little as $240, and in just 45 minutes, Operation Smile medical volunteers can perform a life-transforming surgery for a child born with a cleft.

On May 30th, I will help Operation Smile launch a new campaign to raise funds for 140 such surgeries. The "140 Smiles (in 140 characters)" campaign will unite the Twitter community to change children's lives. I am honored to be part of this groundbreaking campaign.

As the official Twitter Smile Ambassador, I can use my success and energy to help children like Christopher have a chance to live a life filled with laughter and smiles rather than shame and isolation. I think he would be proud.

And that makes me smile.

• For more information on how you can help: OperationSmile.org
• To be a part of the 140smiles Twitter campaign: 140smiles.org
• Twitter.com/adventuregirl
• Twitter.com/operationsmile

Stefanie Michaels is Travel + Leisure Channel's Uberguide Series expert, and has shared tips on Discovery's Planet Green Channel. She garnered the coveted spot as the green lifestyle expert blogger for The Huffington Post and Tonic News Network and has shared advice for The New York Times, CNN.com, Fox News Channel, Women's Health & Fitness, and Elite Traveler Magazine. In just 2 months she amassed more than 450,000 Twitter followers seeking travel tips, and was named Twitter's Top Global 100.