Thanks for posting this informative article on hostels I work for HI where we get lots of enquires from people about hostels regarding what to expect. People often come to us asking if they're too old to stay in a youth hostel which is never the case ( for HI hostels at least).

The mixture of different travellers and the strong social aspect is what makes staying in hostels so great. A lot of people assume that hostels mean staying in a dorm, but as you said, many hostels now offer private (and even ensuite options) for those who aren't so keen on sharing a room and many hostels offer trips and events which can be great for making friends too.