Bridge - Ubuntu Wiki

Bridge (working title) is an indicator providing quick access to previous documents, files and websites related to your current activity.

Rationale

Jan is writing an article for her blog: she checks several Wikipedia pages, discusses some details with a contact in Empathy, takes a screenshot and publishes it. A month later, she opens the article in a web browser: Bridge provides her links to the related Wikipedia pages, the name of the contact and the screenshot file.
Jon is reading an article containing several links, he visits some of them and finds a video he downloads. Whenever he plays the video, Bridge provides him the webpage he downloaded it from and a link to the original article.
Jen is writing a python application. In the process, she reads a lot of documentation and asks questions on Stackoverflow. Whenever she opens her code in Gedit, Bridge provides her links to the documentation she used and questions she asked.
Jin is editing a audio file with Ardour, made of several sound samples coming from an online sound database and from his personal collection. Whenever he plays the finished track, Bridge provides him a link to the sound database and the samples used.

The title of the focused window is parsed to keep only the part relevant to a specific file/website/activity
This string is used to query Zeitgeist for a matching recent event
This event is used to query Zeitgeist for related events
These related events are used to build the menu of the indicator
If it fails, the indicator is not displayed
The process stops until a change is detected in the window title or if another window is focused.

A list of items, relevant to the active window, presented with their preview icon, favicon, mimetype icon or application icon, in this order of preference.
A separator.
A "Focus on <window title>" checkbox item. When active, the indicator icon is dimmed and window tracking is disabled. The Bridge will keep its focus on this specific window.

In the HUD, results from Bridge are presented in the form "Related Activities > item"