I lurk and read from time to time... and whenever I hit the new posts button, it would show me what I missed. which is fine at first.
if I get distracted and hit it again after a short time (maybe an hour?) all the topics vanish and only show what I missed since last recorded time I was "present"

is there a way to let it just accumulate until I hit something like mark all unread as read?
I checked my profile and I didn't find any there...

Thank You!

No, there isn't that function. However, on the Portal page there is a "Most Recent Topics" list on the left side of the page which shows the latest 50 topics in reverse chronological order.

Thank You Rob, that will have to do then... 
alternatively, I suppose I could also just not touch that page til I read all of the topics i want to read.