Why would you want to grab a link to a post? This is an easy way to track student participation in a group. Rather than trying to tally up how many times a student posted or replied in a group, create an assignment where the student turns in the links to either the posts they created or replied to. I use this method to keep track of participation in our Scribe City writing group.
If you notice in the above assignments, the students are posting their writing/replies publicly to the group AND turning in a 5-10 sentence reflection on the process which only I will read. This step helps to build metacognitive thinking skills. Using this process of turning in a link to a post saves me time with assessing student participation and keeps the students writing.