Excellent add-on! Rated 5 out of 5 stars

It makes significantly more then described!
1. It opens ANY shortcut bookmark, not only for search in new tab
2. It opens even javascript bookmarklets
Therefore I have 2 suggestions:
1. It is better that item "Keywords Bookmarks" will appear in context menu anyway, not only if some word/phrase is selected
2. To allow to open the bookmark itself not only in new tab, but also in current (for javascripts, for instance) and even in sidebar.
Let say, left click - in new tab, right - in the same and middle - in the sidebar

This review is for a previous version of the add-on (0.2.1).