"Show More" should ignore new threads when retrieving the next page of threads

If new threads are made on that board before you click Show More, once you do click to get the next page of posts it will show duplicates for the last [X} threads on the board (assuming there were [X] new threads. It would be nice if the boards used a "cursor" (the DB kind, not the display kind) of sorts to get the next 50 threads, ignoring any new ones that were made.

Using this method, one could also implement a "newer threads have been posted" feature. By using a similar method as above, the boards JS could get the newest threads, up to the current first thread.

If well implemented, this could cut down on full page refreshes, in addition to eliminating any duplicates in the results.