Google announced their Custom Search Engine Beta. Like the similar Rollyo service, Google CSE allows you to specify the sites you want searched. You can also tell the CSE to search the entire Google index, but give weight to those sites. It also gives you the option of excluding sites. You can also use patterns to specify parts of sites, e.g. to filter out urls including certain words.

There is an option to include the search form and results in your own site. To see that in action check out this job search page on my site.

One of the nicer features is refinement labels. This allows you to tag sites with a descriptive label that can be used to refine results. If, for example, you label sites in your set using facets, e.g. subject, type, etc., then those can be used to narrow the result set.

You can see the CSE I'm playing with for UX-related sites to see how this works (e.g. search for "sparklines"):

Or try this search of some of the newish niche web design/development job sites:

I've made these CSEs open so anyone can contribute to them by adding other UX-related sites to the list. I've also set the CSEs to limit to the sites specified. I tried with the option to search all of Google, but I noticed a little noise because many of the results were outside of the UX scope. It's simple enough, I suppose, to expand the search by clicking the "Web" radio.

I'm not sure how much I'll actually use this. I stopped using Rollyo after playing with it for a few days. But the added refinement functionalities make this service a bit more useful to me.