Mountain View (we just moved onto the same street as YC)
BloomReach (<a href="http://www.bloomreach.com" >http://www.bloomreach.com</a>) is a small, fast-growing startup that is tackling one of the Internet’s most fundamental problems: helping leading online businesses get their highest quality, most relevant content found by their consumers, when and where they want it.  We're delivering a 95% uplift in non-branded organic search traffic for brands like Neiman-Marcus, William Sonoma, Buy.com and others.
Here's a Quora post why one of our engineers chose to work at BloomReach: <a href="http://www.quora.com/Stormy-Shippy/Posts/There-is-this-little-company-in-Mountain-View-that-I-work-for-called-BloomReach" >http://www.quora.com/Stormy-Shippy/Posts/There-is-this-littl...</a>
Backed by Bain and Lightspeed.  See our advisors here: 
<a href="http://www.bloomreach.com/who-we-are/our-investors-advisors/" >http://www.bloomreach.com/who-we-are/our-investors-advisors/</a>
Take a look at open engineering positions here: <a href="http://jobvite.com/m?37H9sfw9" >http://jobvite.com/m?37H9sfw9</a>
Email jason at bloomreach dot com if you'd like to chat before applying.  Interns welcome too.
We commit to moving through the interview process quickly with you, if you're interested.