Last modified: 2011-03-13 18:06:46 UTC
... and probably for other similar magic words. Take for example Commons main page http://commons.wikimedia.org/wiki/Etusivu?uselang=fi in Finnish with Finnish interface, where NUMBEROFARTICLES appears as 5,809,086 and at the same time on statistics page http://commons.wikimedia.org/wiki/Special:Statistics?uselang=fi with Finnish interface, where the same number appears as 5 809 086. It could do the same with NUMBEROFARTICLES – despite using decimal separator, use spaces to show numbers in groups of three.
Variables like {{NUMBEROFARTICLES}} have the number formatted according to the content language. You can see how in fi.wikipedia it has the second format. I don't think it should be changed for the general case. Although for a site like Wikimedia Commons which is full of {{int: }}, it makes sense.
We're not changing this for the same reason we're not processing accept language. Will cause ooo much strain on the backend. See first part of comment 1. Closing as WONTFIX.