For Maryland and DC, there are a few groups. Some are localized to a single county or a group of adjacent counties, while others cover the entire state. Each one has its own set of rules, most of which are pretty straight forward. Some are stricter than others.
Most groups are pretty consistent when it comes to keeping conversations to a minimum and sharing information specifically about birds that are notable for the region in question.
I moderate a Maryland list with Orietta Estrada and Lynne Parks, "IDEA: Maryland RBA"
(Please actually read the rules. I know it may seem like a lot, but it's common sense stuff built around respect and inclusion.)
There is also an unmoderated DC RBA.
If you would like further information on the above groups, please message me directly.
As for the other MD groups, the respective owners are welcome to share that information. As I mentioned, all groups have different rules and are maintained by individuals who put in the time needed to make these groups run well. None of these groups are owned/sanctioned by MOS, Audubon, etc.
I hope this is helpful.
Thanks!
Dany Sloan
WDC