What is Chirrup?

Chirrup is comment system which uses Twitter as a datastore. Chirrup's homepage can be found at chirrup.angryamoeba.co.uk

Wait - Twitter?

Ah, yes. Go here. Read it. Enjoy it. Come back. We'll wait.

What you need to install Chirrup

Very little!

A little space with a hosting provider who support PHP (i.e. nearly any hosting provider).
N.B. Your host must support curl, which means completely vanilla PHP installations may not work. Any hosting provider worth it's salt will have this enabled by default, however.
The ability to add a piece of Javascript to your site's HTML templates.

Chirrup doesn't need access to a database, and nor does it need any extra components above and beyond an industry-standard PHP installation. While Chirrup does store comments as they arrive from Twitter, Chirrup simply uses a small XML file on your server rather than relying on having a database server.

Is Chirrup compatible with my setup and my visitor's setups?

Probably, and yes.

Chirrup outputs valid XHTML 1.1 markup into your document.
Chirrup's Javascript has been verified working in Internet Explorer 6 and up, Firefox, Safari and Opera.
Chirrup's default CSS has also been verified compatible.

So what's the point of using Twitter as a comment system?

People are following your twitter feed. People are reading your blog. People are discussing things they've read on Twitter. It seems only natural to marry them up.

It's pretty common for people to post links to pages via Twitter, along with a short commentary or opinion. The format is so free, with the only restraint being one of brevity, that many people use Twitter not only to post the daily minutia of their lives but to discuss and communicate ideas. Chirrup is just one the of many, many applications which use Twitter as a platform.

Chirrup simply provides a means to show that chatter on your blog as a set of direct responses to the content you've written. It also provides a means for people to post their opinions to your blog using a technology they already have and use.

How do I set it up?

Head over to the HOWTO page, or the howto.markdown file if you're reading this from the downloaded version of Chirrup.

Chirrup's Secret Sauce

Chirrup achieves its functionality by combining a a few tricks into one neat hackety-hack package:

A caching system. Chirrup stores every message it encounters in a local cache, which means big speed bonuses. Chirrup will, by default, go to Twitter for fresh data every 60 seconds rather than going every time it's asked.
Twitter replies. All comments posted through Chirrup are replies to you personally, which makes good semantic sense. Replies are also handled differently to the bulk of public messages - we have a nice feed of replies to you which we can index without having to spend cycles trawling the public feeds.
Tinyurl integration. Chirrup can build and break down tinyurl's in comments, so it will pick up comments in which the url of your page has been abbreviated by the poster's Twitter client. Chirrup's javascript widget also uses tinyurl integration.
Semantically correct messages. A reply sent from Chirrup contains a link to your Twitter feed, a link to the page being discussed, and the comment - in that order. It read well, and makes sense when read alongside other, "normal" tweets. No weird syntax, no crazy numeric identifiers. A comment sent from Chirrup looks like this:

@yourname http://tinyurl.com/9999 I heartily endorse this event and/or product.

Reporting a bug, requesting a feature

You can do both of these things over at the Chirrup Tails Project. Have fun!