I think our "Be nice policy" is actually really good. For example it starts with:
Whether you've come to ask questions, or to generously share what you know, remember that we’re all here to learn, together. Be welcoming and patient, especially with those who may not know everything you do. Oh, and bring your sense of humor. Just in case.
Be welcoming, patient and bring your humor. These are great words.
In the summary is says:
In summary, have fun, and be good to each other.
We are in this together just as we are in Samsara together. Let's not forget that. We support each other in our individual journey towards Liberation. Buddhism SE is a great platform for doing that.
This might sound full of attachment but i have come to consider Buddhism SE as my "virtual" home. A place where i can go and just be with Buddhism and other people who share the same interests and ways of life. Being nice is so important for this online Sangha to work.
So what does it mean to "be nice"?
It means to treat other beings with respect, kindness, tolerance, helpfulness, harmlessness and good-will (with respect to the noble eightfold path).
I would like to give a reflection-quote from the Sotapatti Samyutta: Veludvareyya Sutta:
"Again, householders, a noble disciple reflects thus: 'If some one were to address me with harsh speech, that would not be pleasing and agreeable to me. Now if I were to address another with harsh speech, that would not be pleasing and agreeable to the other either. What is displeasing and disagreeable to me is displeasing and disagreeable to the other too. How can I inflict upon another what is displeasing and dis agreeable to me?"