A sponge is used more by housewives than professional bakers, but a sponge is still a good yeasted technique.
In the early days of commercial bakers yeast it was just not very reliable, so bakers would "prove" the yeast, or make the yeast prove that it was still active. This is done by putting the yeast for a recipe in some water with a bit of flour or sugar.
This is most useful for compressed, or fresh, yeast, or active dry yeast. Instant dry yeast is very reliable and does not need to be proved.
Typically, the yeast was dissolved in a cup of water with a tablespoon of sugar. The yeast was given 5 to 15 minutes to show it was active. If it didn't bubble, it was time to go to the store to get some fresher yeast.
Over the years active dry yeast has become much more reliable and many bakers don't bother proving it, they just make the final dough. James Beard, among others, suggests that doing this will rob your bread of flavor. So, make a sponge if you are using compressed (fresh) or active dry yeast.