Is there any validity to this?
Quantum Mechanics can give a quantum answer. I refer you to Rhonda's book, ''The Secret.''
There are a few problems though, which Dr Fred Alan Wolf describes if you ever seek to have personal talks with him. HE concludes, that at most parts when tiny actions are involved, that electrons are not in fact attracted by the like. On the larger scales, these conditions maybe applicable.
It is by no coincidence, as Medicine Woman informs, that certain human behaviour will always, (or mostly), attract like minded people.
However, i personally do not believe that all thoughts can have a frequency that alters our reality to any noticable drastic change.
If you want something in life, it requires determination alone, and this is the real secret.