Hi Piadidi,
Unless specified, you should be receiving emails in your gmail account with which you have registered for the MB discussion. So, an email every time a new thread starts or someone replies to a post, is an easier way to keep track of the happenings in the group.
Alternatively, if you go to the MB discussion group,click on Discussions on the right, you shall find the "Topic List" and "Topic Summary" on the top left.The former gives you a list of posts according to date, unless a post has been tagged, which shall be shown at the top. Although, if your messages are not arranged according to date, I have no idea how that can be sorted.
Hope this helps!