Lightweight and extensible blog software?

Well, wordpress satisfies pretty much all your requirements. If you use something like wp-supercache, it's pretty much as lightweight as you can get (caching to static files). It does have a crappy security history, but if you keep up to date you won't have any problems. So, that's what I would use (and I do).

You should also consider Joomla. It has an active community. Installation and setup is straight forward.

Jeff

I think Pivot is very good. http://www.pivotlog.net/

Habari maybe? http://www.habariproject.org/en/

Been using Drupal for sometime now, hands down beats Wordpress, Joomla when it comes down to things like performance, SEO, scalability and just out and out clean code. Yes it does have a steeper learning code but it worth it.

What you mentioned about things like openID, there are numerous modules available and openID being one. As far as antispam I use Mollum which is excellent. There are a lot of themes "Free" available also, give it a shot. Also go out and google for Drupal vs Joomla or any other CMS, there's a lot of good comparisons out there.

I'm wondering how Wordpress is not lightweight; I've always thought of it as lightweight and it seems as such to me. If it isn't though, would you care to explain why it isn't?

I'm running WordPress and it performs admirably in almost all situations. My site gets anywhere from 1200-5000 hits in a day, with multiple pageviews.

We spiked to 35000 hits in one day back in December and WordPress didn't even blink.

I have zero issues with Wordpress. It seems lightweight, scalable, and speedy at generating its dynamic content.

.

@hybinet:

Habari maybe? http://www.habariproject.org/en/

I have never heard of this so I went and checked it out. It looked interesting so I installed and I'm pretty amazed. Why don't more people know about this? Definitely following. Thanks!

@sneaks:

@hybinet:

Habari maybe? http://www.habariproject.org/en/

I have never heard of this so I went and checked it out. It looked interesting so I installed and I'm pretty amazed. Why don't more people know about this? Definitely following. Thanks!

This Habari you speak of looks somewhat familiar to Linode's website.

Thanks for the replies, everyone. I might end up using Wordpress anyway if it handles well, in spite of my reservations.

@lightweight: Wordpress just seems big, bloaty, leaky, and generally ugly on the inside. It reminds me of Perl: you can do a lot with it, and others have done a lot that you can reuse for your own projects, but it's hardly elegant and makes me die a little inside. Another way of looking at it: the latest Wordpress package is 6.9MB unzipped, Habari is 3.6, and Chyrp is 1.6. Mostly irrelevant to the question of quality, but it's still big.

@Habari: I like the design features of Habari. It's like the Python to Wordpress's Perl.

@Drupal: I tried it and wasn't very enthralled, but it was a while ago. It seems that it takes the Author/Timestamp->Title/Body format and tries to throw it at every problem. It seemed to me that everything from the blog to the forum to the wiki felt like the same webapp. Of course this could be due to me not putting enough effort in, but ideally that shouldn't be required. At the moment I just need a blog, and would prefer something that excelled at that right out of the box.

@Joomla: I feel like it may have the drupal problem. If I don't need all the functionality that it can provide, then I'm carrying around a lot of dead weight. It's still worth looking at, but I'm leaning more towards the blog-only solutions.

@Opcode caching: I'm really interested in trying out APC. Sure the speed's nice, but upload progress bars are fun. =)

Thanks again for the comments and war stories. I still haven't made up my mind yet, so the more the merrier!