In Germany, men don't wear cotton briefs at all, and bikinis are two-piece swim suits for woman. For my generation, swim briefs are quite normal to wear, especially if you're going to the pool to do real swimming (for your health etc.) and not just to laze around in the water. If you're going for pleasure, you wear board shorts, and especially the younger generation also tries to swim with them, which of course more difficult than with swim briefs because they increase drag quite a bit.