In 2009, there were eight free blog providers based on WordPress.
Last year, someone compiled a list of 34 service providers, but now only these eight are still operational. I've tested each one, and if you don't mind an English interface, the official one is still the most stable. Here are the eight free blog providers based on WordPress:
Address Introduction Demo
http://www.wordpress.com/ English, officially provided by WP, stable, with ads http://wanganqi.wordpress.com/
http://www.ixiezi.com/ Chinese, privately operated, relatively stable, with ads http://wanganqi.ixiezi.com
http://www.72pines.com/ Chinese, privately operated, relatively stable, with ads http://wanganqi.72pines.com/
http://msnsa.yo2.cn/ Chinese, privately operated, relatively stable, with ads http://msnsa.yo2.cn/
http://www.msnsa.net/ Chinese, privately operated, relatively stable, no ads http://msnsa.net/wanganqi
http://blo9s.com/ English, privately operated, relatively stable, with ads http://blo9s.com/wanganqi/
http://wanganqi.xblogspot.com/ English, privately operated, relatively stable, with ads http://wanganqi.xblogspot.com/
http://wanganqi.blogsome.com/ English, privately operated, relatively stable, with ads http://wanganqi.blogsome.com/