This is the best Meta search engine when it comes to performing real-time clustering of search results. On the left side you will see a list of categories that are relevant to your search term. My own web search results for "bottlenose dolphin" returned a decent list of categories including “Facts about Bottlenose", “Names Bottlenose" and “Species of Dolphins" among others. Clicking on the ~ez_ldquo+ez_rdquo~ sign of each category returned more results. For instance, the "Facts about Bottlenose" category had two additional categories, fun facts and fact sheet, and clicking on any of them returned more results in the SERPs.
The real-time clustering of results can be of immense use for researchers, students and teachers, thanks to Clusterizer, a clustering engine developed by CyberTavern, the owners of iBoogie.
Another great aspect of this Meta search engine is that it allows users to add tabs of their choice from a multitude of options. iBoogie has a variety of tabs categorized under Blogs, News, Food, Government, Military and Technology. So, if you want real-time results from the blogosphere, just check the Technorati or Xanga Blogs search tab. Or if you want to know all about medical terms, check Healthline.com tab and click the add tab button to get it enlisted at the top of the main search results pages. When you want to search about a medical term, click on the newly-added custom tab and start getting relevant results from the website.
iBoogie perfectly fits the “comprehensive meta search engine" description. Users can not only search about images and videos, but can also seek advantage of their deep web feature to access search results from a variety of databases.