The number of people present in the IRC channel is more of a sign that they have a very engaged and active community, which is a good sign for the language itself, for sure, but doesn't necessarily correlate to the general adoption of Haskell as a whole.
A measure like http://www.tiobe.com/index.php/content/paperinfo/tpci/index.... (by no means a perfect one, quite like speed benchmarks ironically) seems to indicate that Haskell still has a long way to go before reaching "mainstream adoption". But you're right about that statement, it was intended more as a humorous jab than a statement of absolute truth :)
A measure like http://www.tiobe.com/index.php/content/paperinfo/tpci/index.... (by no means a perfect one, quite like speed benchmarks ironically) seems to indicate that Haskell still has a long way to go before reaching "mainstream adoption". But you're right about that statement, it was intended more as a humorous jab than a statement of absolute truth :)