Until now most wikis on this list are from Germany, but he plans to aggregates Regiowikis from all over Europe and had already some success as you can see ... (please add your wiki!)
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via eMail
Andere Listen / Wikis
Liste Stadtwikis (Schwerpunkt Deutschland)
Liste at city-wiki-center (International)
P.S.
You find our last Update on Placeblogs here