You can add a search box to your institution’s website that is limited to your content in the OAC, by copying an HTML snippet that's available through your OAC Dashboard -- and incorporating it into your site.
Here's an example snippet:
<form action="http://www.oac.cdlib.org/search"> <input maxlength="80" size="30" name="query" type="text"> <input type="submit" value="go" style="background: #B24415; color: #fff; padding:2px;"> <input value="California Historical Society" name="institution" type="hidden"> </form>
You can see it in action on the California Historical Society's website.