Each day's entry should be stored as a separate record (including HTML markup) in both the client-side and server-side databases.
Each record should have a field for year, for month, for date, and for hour posted. There are people who post multiple entries in a day, and although I have rarely wanted to do that, in some circumstances it could be useful.
Each record should have a field for an author-defined metadata tag, indicating what category a given entry belongs to. (I'll come back to tags a little later.)
Both client and server should have a mechanism for creating a view of the blog entries by filtering on both the time-posted fields and the metadata tags.
Some configurability of blog page elements (header, navigation, blogroll, archive, daily entries) is good, but I don't require infinite flexibility.
Automatic RSS generation.
A right-clickable icon somewhere in each entry, allowing readers to "lift" a database query URL in order to link to an individual entry.
Now, I have no idea what the data storage is like for LJ. But it looks like -- with tags -- this satisfies the other requirements on his list.
So let's tag this entry for "relatives" and "Jeff" and see what we get. :)