Currently Available:
Navigating via a blog’s parents/children/siblings.

Future Ideas:
Expand the number of degrees that you see at once, i.e. 1st degree shows parents/children/sbilings, 2nd degree also shows grandparents/aunts&uncles/cousins/nieces&nefews/grandchildren, etc. This could get a bit crowded and the SQL queries complicated and computationally expensive as the degrees grow.

Ascendents/Descendents. This is basic genealogy stuff, although I’m not sure how to chart it branches in HTML. I could have a table with each row containing all people in that generation, but then you wouldn’t see a nice tree. I may have to do it in VML or something like that.

N degrees of separation (a la Kevin Bakon) - visitor picks two blogs and sees by how many degrees they are related. I’d have to limit the number of degrees (6?) to avoid building huge queries that span the entire database.

Listing blogs by attributes, such as sex, age, language, etc. Not too difficult, but also not too interesting, genealogically speaking. One variation of this would be to have a list of birthday blogs.