@Taliesin answers pretty well but misses one thing. What exactly are open data specific questions? My understanding is that open data should be machine-readable.
Therefore, as I stated in a similar question targetting specifically data extractiona similar question targetting specifically data extraction, any question related to formatting data to be easily readable and therefore Open, is related to open data.
To summarize, questions about data extraction techniques are on-topic because it targets opening up data.
