  We use de-identified data from Facebook Groups to study and provide a
descriptive analysis of local gift-giving communities, in particular buy
nothing (BN) groups. These communities allow people to give items they no
longer need, reduce waste, and connect to local community. Millions of people
have joined BN groups on Facebook, with an increasing pace through the COVID-19
pandemic. BN groups are more popular in dense and urban US counties with higher
educational attainment. Compared to other local groups, BN groups have lower
Facebook friendship densities, suggesting they bring together people who are
not already connected. The interaction graphs in BN groups form larger strongly
connected components, indicative of norms of generalized reciprocity. The
interaction patterns in BN groups are similar to other local online gift-giving
groups, with names containing terms such as `free stuff" and `pay it forward".
This points to an interaction signature for local online gift-giving
communities.
