When a member clicks your widget link and then to read the book, it will show up in your approval history. You can view this information in the following ways:
Go to a the Requests Tab, then on the Title of the book you wish to look into. From here, click View History in the blue menu bar.
You will see a list of your approved members that you can filter based on type of approval - click "Widget Invites" to view approvals via widget. You can also sort based on the column headers.
You can also download the Detailed Activity Report from the Reports tab of your Title Feedback page to view all member activity, including declines and pending requests.