Cousin of the expression folklore.
Streetlore could be often dangerously misleading pieces of information. So, do not follow everything you hear on the street. Pass it through your own common sense reasoning, gather corroborative knowledge, weigh the cost-befit ratio, and possibility of greater risks.
But many a times, you could bump into precious knowledge/solution/nirvana/cure/answers to stuff you have been seeking in a long time and accidentally so while in a public place through the phenomenon of streetlore. In such cases, normally a socially responsible and compassionate stranger would have offered you a piece of advice that you never got from any professional or friend despite frantic seeking.
If you want to spread some precious knowledge through streetlore, please always think and rethink if it is really precious for others and not just you, and not harmful to folks in general. If it was a bit of knowledge that you alone and no one else known to you benefited from, mention that to the stranger who receives your knowledge.
Don't be fixated on 'STREET' part of the streetlore, you could benefit or suffer damage from streetlore that goes on online too.
The other streetlore I would like to propagate and caution you that it may not always work while propagating it is: 'apparently but falsely cold water seems to quench your thirst, but hot water or a hot beverage keeps you quenched for longer'
In India, streetlore sustains the folklore and traditional knowledge. People with half knowledge of a particular cure prod you into trying it. You, would in turn, use your wisdom whether to follow it and consult a tradition-expert, professional or book connected with it and find some help.
The worst examples of Streetlore can lead to entrapment in Ponzi Schemes, or Chickenpox swab trade and related inadvertent infections to children as it happened in the United States recently.