What do the columns in the activity graph mean?
Are the columns, hours, days, or weeks? Those columns are begging for a tooltip telling you what point in time they represent and a count.
Community Responses
I've been wondering the same and just contacted support asking for clarification. I'm curious as to why they don't address this in their FAQ, because it's not intuitive at all.
This is the response that I just received from Rdio:
"The little bar graph shows the number of plays that a song/album has gotten over the past 24 days (each bar represents 3 days)."
It's not very intuitive at all, so it should definitely be explained in a more visible place on the site.