The Forena module can be used for such types of reporting. It comes with all sorts of Sample reports and solutions, such as the Site administration reports, which contain data about the actual Drupal site.
Here are some details about those reports:
- Active Users - A variation of D7's admin/people, including hyperlinks to the Logs for User report.
- Active Users Email - A demo of the ability to send email to all active users of a drupal site.
- Logs for User - Most recent watchdog log entries for a user (specified as a report parameter).
- Role Details - A table displaying all users for a Drupal role (specified as a report parameter), and the Drupal permissions granted to them, with for each user hyperlinks to either view or edit the user's profile.
Cloning these sample reports into custom variations is straight forward. E.g. tune the active users report with some report parameters to only report about user registered this week. Or as I did some time ago in this report (with drilldown links also, i.e. the numbers in red in it):
Refer to my comment in the forena issue queue for more details about the above screenshot.
There is even AbitMORE: this module also supports charting of those data (a typical related requirement ...).
Disclosure: I'm a co-maintainer of this module,
I hope this does not violate the site's policy on self-promotion.