You can very easily set-up segments based on you users' behaviour in their current session. These can be very valuable for targeted advertising, marketing and to gather insights through Permutive Analytics.
To create an in-session segment, just set-up your segment and add this session using the 'time' criteria.
Here, for example, I've created a segment of users who have viewed 3+ pages in their current session.
Please note, Audience Size Estimates cannot be calculated for 'In-Session' segments.