On Ohloh, Ubuntu is reported as "mostly written in C#", and, indeed, if we go to the Ubuntu's languages summary we see that C# has the most LOCs, accounting for approximately 20% of the code base.
If the Ohloh's engine isn't wrong, what is the explanation of this?
The Oloh engine is way wrong. Ubuntu is a quite complex project, and it's difficult to state what is Ubuntu and what is not. But C# is not by any measure the most popular language.
Ubuntu has also much more than 50 contributors and 1500 commits/year even if you only count Ubuntu specific patches.
This site seems to follow some strange mix of Ubuntu and non-Ubuntu projects, it doesn't make sense. It's likely than F-Spot (a big program that is not in the default install base now and it's made in C#) is weighting heavy on that statistic.
