Android :: Google Team - Pin Favorite Threads

I was wondering, why there is no functionality to pin threads a user is interested in. As there is such a high traffic on these groups, it takes time to find the threads I answered to or some I am interested to see how the problem is solved. Sometimes you don't remember the naming of the subject or the user that wrote it and then searching becomes annoying. An easy way would be to pin some threads! I mean the right side is nearly empty an everybody is authenticated when she uses the group, not to just read.