Open Source mapping - wiki-style

Textile markup for python.

Quoted: This is Textile. A Humane Web Text Generator.

Textile markup language.

Quoted: TiddlyWiki is a single html file which has all the characteristics of a wiki - including all of the content, the functionality (including editing, saving, tagging and searching) and the style sheet. Because it's a single file, it's very portable - you can email it, put it on a web server or share it via a USB stick.

A Wiki platform that used the concept of "cards" for navigation.

Quoted: The Google Sidewiki Data API allows client applications to view Google Sidewiki content in the form of Google Data API feeds. Your client application can use the Google Sidewiki Data API to request a list of Sidewiki entries and query for Sidewiki entries that match particular criteria.

You can install SideWiki as a new Google Toolbar option here.

Quoted: Contribute helpful information to any web page. Publish helpful information about any web page right in your browser; read insights in context from Sidewiki entries added by others; share Sidewiki entries through Blogger, Facebook, Twitter and Google profiles.

Google is adding a toolbar feature for placing sidebar notes next to any web page.

Quoted: I am not a big fan of Web annotation services that let people add their own virtual Sticky Notes or comments to Web ...

Play with Textile (and convert to HTML) here.