I have used online lead services many times. You can close several transactions, yes, but many people are unqualified, not motivated, feel no obligation to continues and it takes a lot of weeding to get to a quality client.
I agree with the author of the article.
I totally agree with Kevin. We pay MLS to list our properties, they give to Zillow, Trulia, Realtor.com and then they turn around and charge us to be identified as the listing agent. Realtor.com doesn’t even acknowledge who the listing agent is and we paid for Realtor.com to be developed by NAR.