Post-session (or “post-study”) responses and metrics are usually collected at the end of the study, after all the tasks, in an effort to summarize the overall usability and/or user experience of the product. We've used them most successfully to compare one design alternative against others or one design against its competitors.
Some simple questions can be used just to sum up the user experience for participants. Similar to asking overall ease of use just after a task, you can ask overall ease of use regarding the entire experience on the Web site or section of the Web site. Figure 3.29 shows an example of this.