We used their algorithms to keep BLM off of ND Monday and Tuesday on our local NextDoor was nuts because of all the planned protests. A  few of us leads on ND (over 20,000 members in our area), removed any BLM fundraisers because the official ND rules are "no non-local fundraising." Then, as the SJW started to swarm the main feed with all kinds of BLM articles, demands for changing the rules of police operation, ways to help their cause, recaps of protests, etc. we found a way using ND tagging to get their stories off the main feed so they would get less eyes on their stories and they would eventually disappear into obscurity. Today there is nothing on our ND about BLM. It only took a day using this technique to clear the board. Now it's back to the normal "lost cat, schools are a mess, what was that loud sound, etc," normal ND stuff. It was fun using ND's own tools to control the board postings with just a few conservative leads.