Correlation (Pearson, Kendall, Spearman) Correlation is a bivariate analysis that measures the strengths of association between two variables. In statistics, the value of the correlation coefficient varies between +1 and -1.
According to the MMOHUT games list. Runescape is one of the best yet on free-to-play browser games. There are a few premium features, but there is a free membership trial for 2 weeks.
Video Game / The Overseer Project. The Overseer Project is a browser-based, text-based online game based on the popular webcomic Homestuck, currently in early development. As a fangame, it is naturally free to play and appears to contain no money-making whatsoever.