The "popularity" of most of those languages is being grossly distorted when you convert the "# of Tags" and "# of Projects" data to rankings.
The range in rank value for the stackoverflow tags was from 1 to 56, but the range in "# of Tags" that rank is based upon was from 0 to 82,923 and the data was so skewed that only 11 of 56 languages had above average "# of Tags".
Haskell was well below average for "# of Tags" and Java was well above average for "# of Tags" --
#56 Java = 82,923
>>> mean = 18,770 <<<
#40 Haskell = 1,896
# 1 F# = 0
2) Which gives rise to this kind of bad-math "analysis" --
"Go jumping from #32 in 2010 to #30 today, a number that sounds modest but means that in that time it has improved more in popularity than Scala or Haskell and as much as Java, at least from a rankings standpoint (obviously growth becomes more difficult the more popular the language becomes)."
50% of Tags were for just 3 languages.
The cumulative bottom 1% of Tags were for 31 different languages (including Haskell and Go).
There are some smart people championing Go, but I don't see the benefits.