As usual, there seems to be confusion about the scope of a patent. The scope of the patent is defined not by its title or abstract but by its claims. You have to read the claims.
While there are broad patents that simply end up claiming something "on the Internet" or "on a computer", they are very likely invalid and also (contrary to popular opinion) rather rare and typically anomalous. If you read the claims, you'll see that this one is far from being a patent on a "diary on the Internet."
At a quick glance, the claims require 1) a server sending (a) content of a "diary" and (b) time (presumably related to the "diary content"), (c) privacy level and (d) presentation information along with (e) configuration information to a remote browser, 2) and the browser then dynamically combining information from (a), (b), (c) and (d) based on the configuration (e) all into a cohesive page and displaying it, and 3) then receiving input that changes the information at the server.
Although steps 1) - 2) sound like what wikis, CMS and templating engines have done since forever, as far as I can tell, they always assembled pages at the server rather than in the client. (At least, this was so until 2003, when I last worked with CMS's.)
Additionally, the "privacy level" element seems to be something missing completely from wikis, CMS/template engines and other prior art that I can think of. It may be analogous to access control systems, but access control is evaluated at the server rather than the client. (Otherwise it's akin to saying "Here's data you don't have access to. Don't look at it.")
You might be tempted to think that elements (a) - (e) are just information, and steps 1) - 2) are no different from "sending information and markup from a server to a browser which then combines and displays it as a page", but patents don't work like that. Abstractions and simplifications do not apply well to claims, because, like contracts, they are legal documents, and each and every word is important. To generalize, each and everything specified in the claim has to be specifically described in one or more prior art references to invalidate the claim. Conversely, each and everything specified in the claim has to be performed by something for infringement to occur.