The guidelines also state that children (under-18s) will rarely face criminal charges for offensive tweets or Facebook statuses, for example.
Also if a message is swiftly deleted, blocked by service providers or websites or shown not to be intended for a wider audience, a prosecution is unlikely.
While intended for the CPS to make a decision whether to charge someone or not, the guidelines are also designed to offer early advice to police.
The interim guidelines take effect immediately and are now subject to a consultation process.
More top news
Here are the key moments that will take place on the day Article 50 is triggered and the UK begins the formal process of leaving the EU.
A man has been charged in connection with a crash which killed a four-year-old girl.
Philip, 95, used the vehicle for engagements in London allowing him to travel around the city unnoticed.