Blog entries should have visible dates (usually)
There are any number of blog packages (and blog design templates) that don't make the date of entries very obvious; it's not in the URL, it's not at the top of the page, and perhaps it's hiding in small type down at the bottom of the page. I've come to feel that this is a significant mistake, because of a combination of real blog usability and how blogs are written.
How blogs are written means that you probably never go back to revise and update old entries, even if the information in them is now out of date. However, many visitors are arriving at your entries through web searches and these searches will happily return those old entries, whether or not their information is still useful. So, how does a reader figure out whether or not what they're reading is still good or if it's now probably out of date? Their best clue is when the entry was written.
This is why I've come to believe that blog entries should have the date visible 'above the fold', somewhere around the entry title and other details. I don't think it has to be prominent, but I do think you should be able to find it easily when you look.
I also think it's possible to be clever about this. To view it one way, the older an entry is the more important its date becomes. This implies that you can start out with the date not very visible, perhaps in small type and mostly faded out, and then on older entries you can progressively increase the date's visibility by doing things like fading it in and making its text bigger. How fast this should happen depends on how fast you think entries potentially go stale.
A corollary is that some blogs don't need to do this at all, either because the content of their entries already makes it clear when they were written or because the content essentially never goes stale. My ire about blogs without dates is primarily directed to things like, say, blogs with technical information.
(I'm aware that WanderingThoughts fails on this; the date isn't in the URL and is only visible down at the bottom in small sized text. I'm going to have to think about how to fix that, but it's potentially complex in DWiki's architecture.)