Seattle-based Trailfire just launched. It’s a combination of a social bookmarking service (such as del.icio.us) and a social web page annotation tool (see our coverage of the yet-to-launch Stickis). Basically, your comments and annotations are published on both your personal Trailfire page as well as on the website itself, for viewing by you and others with the Trailfire extension.

To use Trailfire, download and install the extension (available for Firefox and IE). This will add two buttons and a menu bar item. Use the buttons to open and close the Trailfire sidebar, and to mark a page (see screenshot). When a page is marked, a popup appears where you enter a trail name, a title and a description. When you mark other pages using the same “trail name”, they are grouped together. marks can be set to public or private, and users can choose to view just their own, or everyone’s, annotations on a website. Their product roadmap calls for the addition of social networking features like adding friends and having the ability to set group-based viewing permissions.

Annotated pages can also be shared with others, even if they don’t have the extension installed. Trailfire serves the page through their proxy server and adds the appropriate code for the annotation. More information about Trailfire is on their About page here.

Companies continue to tweak the del.icio.us model of social bookmarking in an attempt to find the right mix of features and usability to appeal to a mass market crowd. I like the ability to bookmark and annotate a page in a single action – others may like Trailfire, too.

Trailfire was founded by CEO John O’Halloran and CTO Pat Ferrel. They closed a $2 million venture round from Voyager Capital and individual angel investors.