Rated 5 out of 5 stars
The extension seems great so far, however it wont play well with the Searchbar Autosizer extension. After the entered text clears after the time specified in Second Search, the size won't colllapse as per the Autosizer until I click on the empty search field.
Plus by combining, it would take the need for SA away. The main functions in SA that I find usefull is 'revert to default search engine' - which I'm pretty sure SS already does.. And 'shrink searchbar to button if empty' - and of course, just the expansion of size when entering and shrinking of the size without returning to button. The autosizing also makes this extension incompatible with using the option to show the popup 'above the searchbar', because the text from this extension wont move along with the increasing size of the searchbar.
This would be an almost perfect add-on with that functionality.
There is also a 'SearchWP' extension that might be nice to add to this too. I haven't had time to play around with this one too much yet (I have it disabled right now) - but it allows highlighting of the search terms within the page by clicking on the search term.
All in all, this Second Search extension shows promise at becoming the grand-daddy of all search extensions! Or the mother of all search extensions, if you will.. =)