Sorry kids, not dates with girls... this is gonna get technical:
No, not the dried fruit, either. This is in response to Paul's initial take on the subject of abandoning calendars.
Why are dates important for blogs?
If there aren't any dates associated with your blog entries, how will people have any way of knowing if your post is still relevant or how often you post? Obviously the latter could work against you. However, if your site is entirely context/categorical and somebody is digging through your category "politics" and they come across "the president is a bastard" without a date they'll have no way of knowing whether they'll click the article and get a rant about Bush, Jr. or Bush, Sr. Sure, you are going to argue that "the president is a bastard" is a bad title for this very reason, but there are clearly circumstances where this would be unavoidable -- good title or not. Without chronology, you could very well be seen as inconsistent and contradictory. Your opinions will change, and posts from now and then will be mixed together at random.
All articles need to have some sort of permanent link. Having your old articles fall off the face of the earth never to be seen again seems to be an incredibly bad idea. If you are doing it to cover your ass so you look good, you will get caught doing this, and you will be discredited. Even if you are doing it innocuously, you are hurting your readers. They won't be able to bookmark a good post for later reference. If you want to argue that the old posts are probably no longer relevant -- hell, they probably say things that are flat out wrong and outdated -- and this is why they should be deleted, you are still hurting your readers. The right thing to do in those circumstances would be to redirect the bad, old post to the appropriate good, new post.
Would people ever want to browse a blog by date? Well, I don't really know. You could argue a reader might be like "man, there was this great post, and I remember it was November 2005 because xyz happened that month," so they'd want to find your post that way. However, what is the likelihood that they wouldn't also have enough information to find the article again by searching or by accessing your categories/contexts? They probably would have enough information, but depending on the topic and the keywords and the category, they might have to dig through hundreds of other posts. Of course, you could have posted 100 times in November 2005, so date browsing isn't necessarily any better. If you post 100 times a month every month for 5 years though, your keyword searches and categories are going to get pretty thick. Ideally, the user could use both kinds of browsing simultaneously. Why make life harder for them?
In my opinion, should a blog be centered around a calendar? No, I don't really think so. But I do think posts still need dates.
Just because you are too lazy to have date-based archives...
I have responded to your response to my initial post about Dates and Blogs here: http://paularmstrongdesigns.com/weblog/ia/dates-and-blogs