On a good day, Sverker Johansson adds more than 10,000 articles to Wikipedia. Johansson is by far the most prolific contributor to the online encyclopedia, having submitted 2.7 million articles, or 8.5 percent of Wikipedias collection, over the last seven years. The 53-year-old Swede, profiled in The Wall Street Journal this week, works as an administrator, and has degrees in linguistics, civil engineering, economics and particle physics. …