Blogging in China, any limitations?

Two different online contacts recently asked me about setting up blogs in China.  I write a blog here in Thailand (about tea), but I wouldn't know much about limitations of writing a blog in China. 

The ones posted here in the blog directory use different platforms / host sites, including the two main ones, Blogger and Wordpress, and also others.  Are there any limitations there that wouldn't apply elsewhere?  Is access to Google products  and sites relatively open (Blogger)?

I understand that people can use a VPN to access anything on the internet there but they wouldn't be interested in setting up something questionable, and it would see ill-advised to violate any access restrictions and then post an open publication that shows you did that.  Surely there wouldn't be free-speech restrictions related to writing a lifestyle blog, or about tea?

Would these be blogs that you would write about China from outside the country or within the country?  If you're based in Thailand writing about China, you have nothing to worry about.

All Google products (Gmail, YouTube and Blogger) are completely blocked here.  So is Wordpress.com.  However, a privately-hosted site that uses the wordpress platform is fine. 

Aside from the blanket blocking of certain sites, the enforcement seems kind of arbitrary.  I've read about sites that were suddenly shut down, but very rarely.