Fluentd is a log collector similar to syslog but uses JSON format for log messages. This provides benefits like machine-readability through use of field names and type information without rigid schemas. Fluentd collects logs from applications in real-time and routes them to storage. It supports plugins to filter, buffer, and route logs flexibly to different outputs like databases, file systems, or cloud services. Fluentd is useful for log analysis and helps address issues with traditional batch-oriented collection through rsync.