Recently, I have noticed a cultural bias for the United States running through LW threads. It is perhaps to be expected of an English-language website, but for one that is about, among other things, overcoming bias, it is important to recognize one's own. 

Aspects of the bias I have observed include:

• Using Imperial units over the SI system, which is the standard for scientific literature and discussion.
• Presuming the US by default when it is assumed that no country name needs to be given.
• Expecting reader familiarity with US-specific cultural concepts.
• A tendency to focus on the US first and foremost when talking about worldwide problems and scenarios.

I'm not the first to raise such concerns, either.

By comparison, e.g. the English Wikipedia strikes me as an example of an international English-language project that's relatively successful at recognizing and fighting systemic bias, and a whole set of template messages to mark articles with identified problems.

To quote Wikipedia itself:

The average Wikipedian on the English Wikipedia is (1) a male, (2) technically inclined, (3) formally educated, (4) an English speaker (native or non-native), (5) European–descent, (6) aged 15–49, (7) from a majority-Christian country, (8) from a developed nation, (9) from the Northern Hemisphere, and (10) likely employed as a white-collar worker or enrolled as a student rather than employed as a labourer.

The reason I haven't mentioned other obvious biases, such as gender, age, education, or First World biases, is because those (in my experience) tend to be more subtle here on LW and because I'm myself subject to some of them. However, I might cook something up on them later.