It’s a bit strange, almost nobody seems to be doing this. Looking through a sample of personal websites, very few of them has links to other personal websites. A hyperlink isn’t a marriage proposal. It is enough to find some redeeming quality in a website to link to it. It costs nothing, and helps bring traffic to pages that you yourself think deserve it.
If we actually want these small websites to flourish as a healthy community, we need to promote each other much more than we do. It is advertisement, yes, but in earnest. I like it when other people link to my stuff. What sort of hypocrite would I then be if I only ever linked to my own websites?