In Tidings, under Slashdot Nodelet added, it says: "A new nodelet ... It presents the latest 15 news items ...".

I just counted them and it's currently 15. Perhaps a coincidence; maybe that's all that Slashdot serves up; I don't know. It seems like a reasonable amount.

There are currently 30 under HackerNews nodelet; this seems like a lot.

At the end of the day, I'm not really that fussed. Don't change anything on my account. If others want it changed; I'm happy to go with the consensus.