Google just announced something that I’m really jazzed about: Google Custom Search Engine. Several people mentioned that Google’s Accessible Search was built by using Google Co-op under the hood. Co-op has opened much of that power up to the public, so that anyone can build a custom search engine.
Most custom search engines (whether it be Google’s free sitesearch or Yahoo! Search Builder) only let you select one site to search, or you can offer websearch. Even Rollyo only lets you search over 25 sites.
This new offering lets you easily add hundreds (thousands?) of urls. You can search over ONLY the sites you choose, or (my favorite) you can apply a boost to the sites you choose, with regular websearch as a backfill. That’s really nice, because if your chosen urls talk about a subject, you’ll often get matches from those urls, but if the user types something completely unrelated, you’ll still get web results back. So it’s a true custom search engine, not just an engine restricted to showing matches from some domains.
You can also choose to exclude results from different sites. As far as I can tell, this happens in pretty close to real-time, even for complex url patterns. For example, I added the pattern “google.com/*” and started to get results from the Google directory, so I excluded “google.com/Top/*” and the Google directory results went away immediately.
The look and feel is also customizable. Search results can open up on google, or you can do an iframe to open results on your own site. The former option lets you pick some colors and a logo to customize; the latter option lets you fully integrate the search results into the look/feel of your site because you just wrap your preferred chrome around the iframe. If you’re a power webmaster, you’ll want to play with the iframe option.
Lots of other nice features are tucked away under the hood. For example, there’s a bookmarklet (Google Marker) so that if you’re surfing the web and find a site you’d like to add to your search engine, you just click and that site is instantly added to your search engine. And it wouldn’t be based on Google Co-op if you couldn’t choose to allow volunteers to edit your search engine and add new sites if you want. 
When I played with the first version, I wanted to avoid the standard stuff where you plug in 1-2 sites and get a custom search engine that isn’t blood-pounding-ly exciting (”Oh, a search box, and it searches. Great.”). So what I did was take my feeds (I was using Bloglines at the time) and exported it as an OPML file. Running a command like
cat export.opml | grep "title=" | cut -d'"' -f6 | grep -v '^$' | sort | uniq
was enough to get the blog urls that I was reading (not the feed urls), and I threw those urls into the custom search engine.
And just like that, *BOOM* I had a search engine that covered 70+ blogs in the search/SEO industry. If I searched for [bug], it would return search engine bugs, not bugs in general. OPML-import was so much fun that the Co-op folks promised to support it (I know that importing from Bloglines works; importing from Google Reader might still need a tweak to the OPML parsing). It’s nice that every blogger can have a custom search engine that is centered around their interests.
There’s one tidbit that didn’t interest me much, but readers will probably be interested to hear. If you build a custom search engine, the Co-op folks provide a way to share revenue if people click on your search engine’s ads. Offering revshare is a great way to take a useful tool and get even more people interested in it.
Which leads to my personal take: there’s companies that tackle search for specific verticals (Trulia for real estate, Truveo for video, Kosmix for health and other topics, Powerset for natural language, Guruji for India). Those companies work hard to bring something special to their vertical search. But there’s a tier below “I want to get VC money to do vertical search,” and I think this product could enable that. In the same way that AdSense enabled a lot of very good content creation in different niches, Custom Search Engine could help a lot of people who want to make a search engine, but would be happy doing it not-as-a-VC-funded-startup. Anyway, this whole personal take is wild speculation, but it would be neat if it turned out to be true.
I do think that this launch will kick off a lot of opportunity that not everyone will see or understand at first. For example, the first person to make a truly kick-butt search engine about biking will likely start to attract volunteers and traction and first-mover attention, and could very well become the authority search for that niche. I think that this launch could kick off a wave of search over a long tail of niches; rather than a big vertical like “health,” someone could make a search for the much much smaller “health at every size” movement. Or juggling. Or insurance companies. Imagine your favorite niche, which could be as specific as a small-town or as broad as you want.
Give the Google Custom Search Engine a try. It’s easy enough that you can make a search engine quickly, but there’s a lot of power under the hood.
