This past fall I put some tomatoes in the ground late in the season, purely to find out how rich my soil was. It was too late in the season to fruit. Anyway, On one of them I decided to tie down some of the branches (touching up on my MJ techniques). It definately made it bushier and it encouraged new growth in the middle. Some of the leaves on the tied down stems didn't know what to do. One great advantage to northern growers is that it seemed to help keep it from freezing as much as the other plants I had near it (I assume from ground warmth being released as it got cold at night). In the end it took up alot of room, but I don't know if it benefits/hinders the amount or size of fruit compared to traditional methods (like i said it was too late in season). And like misshestermoffitt said, keep the vines off the ground and also the fruit, because it can also rot easier. Try it, new ways to grow are fun.