Just came across this.
Not done it before, but will be trying it.
When growing cordon tomatoes, it is common to pinch-out the side shoots which form between main stem and leaf stem.
I have just discovered the alternative strategy: to remove them with a proper pruning cut, and to pot them up to grow on as cuttings, They won't all survive, but, conditions being favourable many will grow into more mature plants. They take faster then starting from germinating seeds, but mature later than the parent plant. As such if brought inside, or under glass, they serve to extend your tomato cropping season.
Worth a try, I guess.