AnnoTabe for Chrome
More About AnnoTabe
This extension lets one annotate tabs with extra information. This information can be associated with the particular tab (by unticking the "persist" option), or just the page URL. This is useful both for remembering why you had a tab open, and for recovering from crashes.
The extension will have a yellow icon on tabs with annotations.
One can also view a list of all the annotations, and go to the relevant tab directly from there.
See http://softwarerecs.stackexchange.com/a/1913/19 for more information.
Special thanks to @TildalWave for the icon!