Although certainly not the comprehensive or rigorous information you are looking for, google trends can provide some interesting insights on a broad scale. For example, while effective altruism is showing strong growth in terms of search frequency, it is still searched for 7 times less frequently than Peter Singer: http://www.google.com/trends/explore?hl=en-US&q=Effective+altruism,+/m/05xnb&cmpt=q&tz=Etc/GMT%2B8&tz=Etc/GMT%2B8&content=1
Although certainly not the comprehensive or rigorous information you are looking for, google trends can provide some interesting insights on a broad scale. For example, while effective altruism is showing strong growth in terms of search frequency, it is still searched for 7 times less frequently than Peter Singer: http://www.google.com/trends/explore?hl=en-US&q=Effective+altruism,+/m/05xnb&cmpt=q&tz=Etc/GMT%2B8&tz=Etc/GMT%2B8&content=1