Eastman’s Online Genealogy Newsletter mentions that Danes are going to be returning (optionally of course) to patronymic names. This goes back to the Viking tradition of naming a child after the father’s first name (mother’s now!) and adding “son” or “datter” (daughter) to it.
Until the late nineteenth century, patronymic naming conventions were common in Scandinavia, Wales, and a number of other countries. In fact, patronymic names are still used in Iceland. Now Denmark is returning to the tradition of their forefathers.
If your doing Scandinavian research, you’ve run into the “Svensons” and “Robertsons” and the like. It makes for a challenge.