A list of blogs primarily concerned with Map History can be found at http://www.maphistory.info/topics.html#weblogs.
A small selection of blogs is listed below:
Barron Maps blog. Focuses on decorative, satirical, pictorial & propaganda maps and associated mapmakers, illustrators & artists of the 19th and 20th Centuries.
Cartographers' Guild. A forum created by and for map makers and aficionados.
ICA Commission on Map Design - MapCarte. Frequent posts.
Literary Geographies. Includes discussions on, for example, on literary geography and mapping.
Mapping London Blog. "Highlighting the best London maps."
The Map Room. A blog about maps by Jonathan Crowe. Closed 30 June 2011 (but still available for viewing) and returned in January 2016.
Maps Mania. An unofficial Google Maps blog tracking the websites, mashups and tools being influenced by Google Maps.
MapUtopia. A space dedicated to the heritage of cartography and maps especially from the view point of modern digital information and communication technologies.
Strange Maps. A collection of web maps that the editor found weird, strange, and interesting. It is also a blog, so you can comment on the maps.
Views of the World: worldmapping beyond mere description. Research blog of Benjamin D. Hennig. Includes equal-population maps and cartograms.
Warping History. Blog for the presentation of results and discussion of mathematical methods in the study of the history of cartography.