There are few things as delicious as fresh strawberries. To keep your plants producing their best, it's important to remove the "runners".
Runners, also called stolons, look like small off-shoots or new plants that your mother plants send out. Not all varieties of strawberries will produce runners, for the ones who do it is essential to keep them under control. While you may be thinking, "more plants equals more strawberries", what really happens is your plants put a majority of their energy into supporting these runners instead of producing berries! This leads to a smaller yield of fruit.
Follow the runner down to the base of the plant and trim it off with a pair or sharp shears or pruners.
If you are trying to expand your strawberry patch, you can let a few of these runners go. They will send off roots and establish themselves into the soil. Once the new plant has established the stem connecting it to the mother plant will dry up and fall off.