Like the universe, the Internet is expanding. But while the growing billions of Web pages mean there’s more information available than ever before, they also make perusing the Internet for meaning even harder. Currently, Web-search algorithms are getting the job done, but the meaningfulness of their results isn’t improving as quickly as the Internet is growing.

Now Google is offering a tool that could provide more-selective searching. But instead of overhauling its algorithm, it’s looking to harness the power of the masses to add authority to search results. On Monday the company announced a tool that allows people to build custom search engines for their own Web sites or blogs that have, at their core, the company’s popular search algorithm.

The new product, called Google Custom Search Engine, will let people winnow the searchable Web and add value to search results. To customize a search engine, users collect the sites or pages of interest, and, if they like, they can selectively rank them. In addition, users can more or less tailor the look and feel of the search on their site.

The idea is called vertical search, and it’s been around for a number of years. Vertical-search engines stick to a topic, searching within a select number of pages that include information about, for example, health care, video games, or programming code. Kosmix and Krugle are popular examples.

Google is not the first company to provide tools so that the average blogger or Web master can make his or her own vertical search. Yahoo also offers its own customizable search-engine tool, and so does Rollyo.com (as in “roll your own search engine”). But Google differentiates itself mainly with its brand, its well-known page-rank algorithm, for those pages not ranked by the user, and also by incorporating AdSense into the product. When an AdSense advertisement–positioned next to search results–is clicked, Google makes money and shares a portion of the proceeds with the search-engine builder.

Google’s Custom Search Engine could benefit both Web surfers who want to know, for example, what sites their favorite blogger finds interesting, and also bloggers and organizations that want to provide expertise through the search function on their sites. One of Google’s featured customized search-engine examples is Realclimate.org, a site that provides opinions from experts on climate change. Realclimate.org is using the tool to add its seal of approval to sites found through its customized search engine. The reasoning goes like this: if you trust a site, then you’ll likely trust the results from its customized search engine as well.

The results of these mini search engines could be useful to those who are looking for information from a trusted source. Additionally, the tool could be financially beneficial to those who participate in AdSense. But the impact of Google’s Custom Search Engine is potentially larger than simply stimulating the rise of boutique search engines. Incorporating the results of thousands of small, “expert” searches into its search results could also help Google’s general search engine grow with the Web.