(CNN) -- For the past year, Laura Miller has been living a double life of sorts: administrative assistant by day, secret agent of kindness by night.
The 32-year-old Duquesne University employee only recently revealed herself as the woman behind "Secret Agent L," a giver of random acts of kindness that has been brightening the days of unsuspecting Pittsburgh, Pennsylvania, residents since July 2009.
The project began, Miller says, with the birthday of one of her blog readers who had become a close friend. But instead of asking for the latest book on the best-seller list or an iTunes gift card, the friend suggested Miller perform an act of kindness in her name.
So with a single, lavender hydrangea bloom tucked under the windshield wipers of a random vehicle, Secret Agent L was born.
Miller used her friend's birthday idea to launch a new blog documenting subsequent secret missions, posting photos of the gifts -- all inexpensive to fit within her administrative assistant salary -- that have included $5 Starbucks gift cards, a roll of quarters at a laundromat and decorative cards emblazoned with uplifting quotes.
The gifts are all tagged with a business card printed in "secret agent-y" type, she laughs. Her tagline: "All-Around Swell Chick."
The blog -- with the help of Twitter -- took off, and Miller now has about 80 "Affiliated Agents" across the United States and abroad who are implementing the idea in their cities.
Her favorite mission came on Valentine's Day when she took blank notecards and wrote inspirational messages about how the holiday "isn't just about romantic love."
"I wanted people to know that today's the day you can celebrate love for your own family, your own friends and your own life," she says. "I left them all over the city, and I just thought it felt so good."
She tries to do at least one mission a week, but notes "if I had the money, I would do it every single day," calling the project "one of the greatest honors of my life."
Miller says she decided to reveal her double life at a coming-out party last month to help advance her charitable efforts. The party was a fundraiser for the National Alliance on Mental Illness, an organization "near and dear" to Miller, she told HLN's "Prime News" on Wednesday. More than $1,500 was raised, she said.
"I think people are so hungry to not feel alone and not feel weird and that they don't matter," she says. "I think people really want to feel valued and noticed because there's so much hurt out there and my project is an attempt to heal some of that."
She hopes her anonymous gifts will help at least bring smiles to those going through a tough time -- though she never sticks around to see who finds them.
"I think that's part of the fun -- it's just sort of putting the gift there and leaving, and just knowing that somebody's going to get it and it doesn't matter who," she says.
She often receives e-mails afterwards from gift recipients to her secret agent account.
"One of the sort of themes that I've noticed in these e-mails is that they all seem to find things on days when they're having a really bad day," she says.