Carbon Ads is a wonderful company. They provide an excellent service. However, per Rollbar, Code Sponsor performed better than they did at about 1/3 the cost. What does this mean for the developer? Scaling. Rollbar was able to scale their budget because Code Sponsor provided more interested developers to their product along at a much lower rate.

What Code Sponsor is is a mashup of Carbon Ads, Open Collective and Read the Docs (with a hint of grassroots marketing demonstrated by Wesbos). The 40% was enough for developers. I paid one developer last month over $600. Two others earned over $400.

Finally, Code Sponsor was available to every open source project. The popularity of the project is what self-governed the amount of money they would receive.

Carbon Ads also does not provide any visibility into what is going on. I have taken extreme effort to give sponsors and developers full visibility into their traffic patterns. Daily statistics and charts. This allows sponsors to immediately know how their campaigns are doing and shift if necessary.

Carbon Ads is great, but they are a black box and sponsors want more.