If you’re Indonesian and you create a blog, you might prefer using indonesian language rather than more universally accepted language like English. Some mixed it up a little using both language mainly because you don’t give a damn to translate it in your blog main language. Well, there’s some advantages on using either one of the language on your blog.

Indonesian language  :

• Easier to write a post because you’re writing using your native language.
• You will be accepted on Indonesian reader because it’s easier to understand.
• Reader will easily guess what the writer’s nationality is.

English language:

• Harder to write unless you’re already so good beyond belief with your english.
• Your readers’ circle grows because foreign people (expatriate included) that understand english can read your blog.
• Although it somewhat obvious, reader can be confused with your nationality.

The main thing is what the purpose of your blog is. If you’re creating blog as your diary, you’ll prefer an indonesian blog, but if you want to get more various kind of reader or to encourage indonesian people to learn english, try to write your blog in almost grammatically correct English