There are round, circular spider webs are on my lawn. What should I do?

FAQ
Question: 

There are round, circular spider webs are on my lawn. What should I do?

Answer: 

The horizontal circular webs were created by various spiders collectively called grass spiders.  They are harmless to the grass and ecologically beneficial as predators.  The webs accumulate between rain showers and mowings.  They are especially noticeable on dewy mornings.  No control is needed.