^{Varnish is our new forcefield}

After extensive testing of various caching techniques, we have just enabled additional level of pages caching for anonymous users. We are using Varnish to do the hard job, keeping Lighttpd serving Wikidot pages for logged-in users.

Pages are cached for 3 minutes, and subsequent requests of the same URL to our backend service (based on PHP FastCGI processes) are queued in order to improve overall stability and performance.

Caching is applied only is the following conditions are met:

• it's a wiki page (not uploaded file, login screen, AJAX requests etc)
• user does not have session cookie set (this basically means users that are not logged in)
• page is accessed with http, not https

At Wikidot, we try very hard to balance the feature set on free accounts vs paid accounts. On one hand we want the free option to be tempting enough for people to start using Wikidot and get hooked, on the other hand we would like to offer an even more tempting option to choose one of our paid plans that provide even more features that help running successful sites.

Based on the feedback we received from our users, we decided to remove a few important limitations from free accounts that, according to several opinions, are real deal-breakers when starting with Wikidot.

Try to imagine a situation when you're gathering some people and together creating your new project, e.g. new Internet service. Everything starts from an idea, then you make a plan and try to introduce a completely fresh, magnificent solution that will rule the world. Ok, that's for the beginning.

Yesterday we replaced ListPages module with its new implementation. It works exactly the same for users, but is much more elegant for a programmer.

The module is now divided into two layers. One layer is selecting pages (named SelectPages API) based on criteria and the second layer is displaying the pages using given format. SelectPages API is reusable so we will use it at least for generating RSS feeds (so that they can have the same parameters passed by URL as ListPages has).

I would like to apologize everyone who was trying to use Wikidot for the last few hours, but could not log-in or could not edit pages, without getting any reasonable error message from Wikidot. It took us more than a crazy hour to nail the problem and fix it.

The problem was caused by a piece of profiling code that was added to Wikidot by one of our developers. The code was added outside of our usual workflow, not even through the our version control system (git), thus skipping the internal review process. Moreover, the code was causing an error in a few places, but was silently damping all error messages, and not leaving any trace in the logs. This fooled us and we were rather suspecting lower-level problems with our main server.

Attention: this post is highly technical, mostly suited for experienced Wikidot users.

Recently I have found a nice way of creating sites for someone else (for your family, for your students, for your clients) using Wikidot. I'll explain how to do that but first, let's see what I've tried to achieve:

• I need to build a website that user can edit in a friendly way, but can't break easily
• this requires separation of permissions
  • creator — creates the website, graphic design, structures, prepares everything for the user
  • user — can edit content — add news, edit texts, upload photos and (optionally) delete comments
  • visitor — can view pages and (optionally) post comments
• no experience with Wikidot or wiki syntax should be required for site user
• nice URLs like http://your-domain/news, http://your-domain/gallery, …

This is more or less what CMSes¹ do, but now done entirely with Wikidot.

I really need to have a good reason to talk about events not directly related to Wikidot, but the news from Ning I have just read stunned me. Ning is an increasingly popular "social network builder" — you can create a site, invite friends, upload photos, set up a forum, discuss, share etc. Much like on Wikidot.

Yesterday, one month after Jason Rosenthal replaced Gina Bianchini as a new CEO, Ning announced that they will cut 69 jobs and completely shut down their free service. Ning will remain as a paid-only service. Needless to say, this really upset a lot of its users. Although Jason claims that 75% of their traffic comes from premium sites, vast majority of sites and users are still free.

It might seem that Ning is sending a clear message: "free does not work". It might sound scary, taking into account many similarities to Wikidot. Actually, I do not think this is true at all. Providing free services is very difficult and we know it from our own experience. But Wikidot has been offering free wikis for more than 3 years with large success.