From Wikipedia:

The phrase Law of Attraction, although used widely by New Thought writers, has a variety of definitions. Turn-of-the-20th-century references conceptualized the law of attraction as relating to physical structure and to how matter develops. A more modern consensus among New Thought thinkers is that the Law of Attraction says people's thoughts (both conscious and unconscious) dictate the reality of their lives, whether or not they're aware of it. Essentially "if you really want something and truly believe it's possible, you'll get it", but putting a lot of attention and thought onto something you don't want means you'll probably get that too.

Widespread popular interest for the law of attraction reached its peak after the release of the The Secret, a 2006 cinematic release. After the film's release, the book Law of Attraction: The Basics of the Teachings of Abraham by Esther Hicks and Jerry Hicks made the New York Times Best Sellers list, drawing more attention and interest to this topic. Prior to this, the couple had been in the New Age field since the 1980s.

Law of Attraction is also used in seminars and workshops by New Age spiritual teachers like: Darryl Anka, Steve Rother, Norma Victor, Jane Roberts, Magenta Pixie and many others. They used a process known as channeling in which they claim a higher consciousness will use their body to convey different messages. It seems that the channeling information has a positive effect on the people that apply principles as law of attraction, and so it has grown in popularity in the last decade.

In 2007 Rhonda Byrne, the writer of the bestselling book The Secret, had become so popular that she was interviewed on The Oprah Winfrey Show. By the time Byrne went on Oprah the book had already gotten its break on the Ellen DeGeneres show and was "hugely successful". Oprah aired the first of two segments on February 8, 2007.