The Wikipedia entry http://en.wikipedia.org/wiki/Ethnologue fails to have a 'criticisms' section, which is odd as it looks like a festering pile of crap to me. Note in particular the entries for artificial languages.
http://www.ethnologue.com/show_family.asp?subid=90708 Why is Esperanto down as a French language? And I bet there are more Ido / Volapuk / Klingon speakers than Interlingua.
Europanto is essentially a Franglais style joke, and yet it gets an entry. Mind you even the Wikipedia entry is rather po faced, though the fact that it is just a joke is extensively covered on the Talk page, which has had the usual Wikipedia edit / protection wars etc., demonstrating the important principle that you have to look at the page and the talk page.
Note also the rather dubious and dubiously worded entry about Polari http://www.ethnologue.com/show_language.asp?code=pld
It is a shame that The Ethnologue looks rather bollocks because I quite like the idea of there being separate male and female sign languages in Ireland "There are informal male and female sign systems. Females learn the male system during dating and marriage", and there being something called Old Kentish Sign Language.
By the way, some searching has just revealed that, as with Chombo, Bill Gibson didn't invent the use of the name Volapuk for the use of Latin letters for Cyrillic ones when texting etc. http://en.wikipedia.org/wiki/Volapuk_encoding (although, of course, the talk page disputes the fact that anyone calls it this).