I used Rollyo to create a list of websites called Saturday Adventures. I included the sites I usually use to come up with outdoor activities to do on weekends. At first, I was confused because I expected the tool to just make a list of my websites, much like I do on my library website. But his tool is actually about creating a search engine to look through those sites for specific information. What I learned is that you want to be very speicific about the sites you include on your list. Sites like "National Park Service" will yield way too many results if you are only interested in things to do in the Bay Area.
I can see this tool being useful for teachers who want kids to only use specific sites to search for information. Again, you would have to test it out once you have created a list to make sure the results are not too narrow or too broad.
The link to my search engine "My Saturday Adventures" is http://rollyo.com/christobel04/my_saturday_adventures/