It just looks messy to me, pulling the color off the image with a waterbrush.
What I really enjoy is to pull color onto a piece of wet watercolor paper. I mostly use distress inks for this technique, but I've also used watercolor crayons and ink pads. It's just so organic and each piece is unique. It's really simple, too.
Something else that's fun is to sponge on ink in bands of color and spritz the piece with some water. The colors react and blend in different ways, depending upon the type of ink.
I used distress watercolor markers on the blue and green "happy" card and I love how they blend; it's almost a batik effect. The purple and red on the birthday card were sponged on from dye ink pads and I found that when spritzed with water. the droplets lifted color and left a bit of white or a very light version of the color in the center of each.
I think the artsy-est of all the backgrounds happened when I scribbled my distress markers onto a piece of plastic and spritzed the water onto the ink to create pools of inky droplets. I dabbed my watercolor paper onto the pools a few times until it came out like this:
I don't think I'll be done experimenting with watercolor techniques any time soon... they make it really easy to feel creative and to step outside my predictable clean and simple style. Can't wait to try some more ideas tomorrow!