My Activity Score is still only 150, but I am the tenth member on the list. Why?
@Yutaka - The list on the Exchange page is actually affected by the filtering settings you have selected (see the top left of the page). To see the full list, select all members studying all languages from all countries 
Thank you for your information, Alex.
My Activity Score is now 280. I am the ninth on the list.
I am now the eighth. Just below Skyblueteapot.
I am the first among those who are learning English and whom I ‘friended’, but the eleventh among my ‘friends’–this means those who were ‘friended’ by me-- who are learning ‘all’ languages, or who are actually learning ‘more than one’ language. Just below SanneT.