At the top of the activity feed, there are a series of metrics that describe the total activity of the user within the group, and the total activity of all users in the group.
Reads are the number of documents that have been read.
Resps - are the number of micro-responses that have been created on documents.
The indicate replies - that is the number of response created in reply to another user's micro-response.
Long is the number of Long Reads.