This geographically organized plot thread actually began in Ring of Fire in Flint's novelette "The Wallenstein Gambit" which is set in Bohemia, Austria, and Germany, which tied into stories in various Grantville Gazettes.
For example, the Baen's bar forum, known as 1632 Tech, has been a prime force behind the many works in the popular alternate history 1632 series under the aegis of Eric Flint — especially The Grantville Gazettes.
The Grantville Gazettes — This article covers various common matters on the sub-series in depth, in particular the Phase II experiments with an eMagazine and Phase III (ongoing) maturation of the milieu using collaborative fiction.
Separating 1632-verse history from the internet web fora at Baen Books web site Baen's Bar is impossible, for the forum has shaped the series, as the series has, in part, shaped the forum.