My thoughts are that 1) The 20% number is exaggerated and 2) even if it isn't, statistics are completely meaningless without context. There's nothing in the graph that proves that the declines in the other methods people use to meet their partners are a result of online dating being a better method. There are undoubtedly other factors at play here. Take work for example: the fact that fewer people are meeting at work then they were 40 years ago probably has a lot to do with the declines in male participation in the workforce, and that dating in the workplace has become less socially accepted because of sexual-harassment lawsuits, bands on workplace relationships, etc. Fewer people are meeting at church, because obviously in our increasingly secular society, fewer people are attending church in the first place. I see no evidence in this graph that online dating is making dating any better or easier.
see the review