Hi. What is China Mobile Communications ? I'll look it up. DONE :)

750 will stop sites other than your own from accessing, so if you don't want your media files to be globally available then 750 would be fine.

That would mean if you run more than one site then one cannot access the other.

Then there is the issue. If none of the media/xxx/xxx/xxx files are executable then 754 would do.

I do keep 755 in the overall /media/blogs/ directory as I have css files that require 'execution' .

I can also access my documents and images from outside the blog. It does mean there can be extra server load and the images have to be non-personal etc.

@amoun thanks a lot for your prompt help! I will set chomd to 750 for all private blogs and try 754 for those who are bothered by China Mobile Communications.
I am glad that you continue supporting us b2e users - thanks, that is really awesome!