Buckets are a handy way to group together small to medium size lists of records or items. Bucketing tools are found in Cataloging –> Record Buckets or Cataloging –> Copy Buckets (see link for instructions on creating and managing buckets). There exists also a tool for putting people into buckets, in the Circulation menu, but we hardly ever use that..
Buckets can be private or shared. Every bucket gets an ID number (e.g. #58); to share a bucket with colleagues you can give them this number. To access a shared bucket: Buckets –> Shared Bucket –> Bucket ID