"Aging charts show the age of the contributors still active using the date of their first contribution in the different data sources."

Syntax is poor, I first thought "using" was subordinate to "[who are] active" while it's a subordinate of "show" (neither makes much sense): at least add a comma before "using", or better make it another sentence because it has no relation to the first.

Additionally, "using the date of their first contribution in the different data sources" is a useless detail, while you forget to say *who* is considered "still active": people still active in the last 3 months? 6? last year?
Mandatory reading: http://infodisiac.com/blog/2009/12/new-editors-are-joining-english-wikipedia-in-droves/

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Severity: normal
URL: http://korma.wmflabs.org/browser/demographics.html