Many Neighbourhood Watch mgroups use social media to share information about what’s happening in their localities - WhatsApp is the usual and found to be most effective, but Facebook and others are used. Choose what’s right for your locality. But rules of usage should be clear about what to use and when.
Here are some guides:-
Be clear about the purpose of the Group - for Neighbourhood Watch and not for personal, political, or business purposes
Never reveal or disclose personal information
Never be offensive or abusive - never use expletives
Respect individual privacy
Avoid unnecessary casual or irrelevant ‘social chat’