Dogpile is unusual among most of the major meta search services in that it doesn't mix results from different search engines together. Instead, it keeps the results from each major search engine separate from the others. In a way, Dogpile "stitches" the search results together.
Dogpile doesn't show you which search engines will be queried before you perform a search nor tell you the order in which results will be displayed. However, you can find this information by selecting the "Custom Search" option at the bottom of Dogpile's home page.
The Custom Search option also lets you control exactly which search engines are queried and in what order they will appear. By making use of this facility, you can easily make Dogpile sit up and behave in the way you prefer.
For the most part, paid listings are not identified as such. Some type of "listing fee" notice follows the results from only three of the nine paid placement services carried by Dogpile: Bay9, FindWhat and Sprinks.
You are shown exactly which search engines were queried clearly at the top of Ixquick's search results page. In addition, it is extremely easy to use the box at the top of the search results page to select exactly what you want.
Paid listings from GoTo are not identified as paid listings. The Ixquick "Spotlight" area, which is well separated from the main search results, seems to also carry paid links from Sprinks or GoTo. Also, "Excite" links are really FindWhat paid links that appear on the Excite search results page. Excite's editorial results do not appear to be carried.
Finally, HotBot results bring back results from Inktomi, rather than Direct Hit.
Mamma doesn't display a list which search engines are checked, either before you search or within the search results. The Power Search page isn't much help, either. Reached via a link on the Mamma home page, the Power Search page seems to list all the search engines that Mamma queries. In reality, Mamma also queries some paid placement services not listed on that page.
Also, the Power Search page didn't work properly. For example, results couldn't be restricted to just Ask Jeeves (and these were really Direct Hit results), while restricting to Infoseek (which is Go, which uses GoTo results) didn't work at all.
In order to understand which search engines Mamma carries, test searches were performed several times, and the search engines that actually appeared were counted as being carried. The main service missing was GoTo. GoTo is listed on the Power Search page as a default engine queried, but no links from this paid placement service were spotted.
Paid listings present in the main "Mamma's Search Results" area were not identified as paid.
The search engines providing results are shown at the top of MetaCrawler's results page. These can be significantly different from the search engines initially queried, due to timeouts (which are shown at the bottom of the search results page).
It is possible to increase the time MetaCrawler allows each search engine to respond, which will reduce timeouts. This can be done using the "Customize" tab at the top of the MetaCrawler home page. This page also makes it easy to select exactly which search engines MetaCrawler queries.
MetaCrawler is the only major meta search service to provide access to Google's popular results. At least, this is promised. In reality, Google results weren't available when using the Customize option in an attempt to get listings only from Google. This might be a temporary glitch.
Paid links were not identified as such in any way.
Search.com shows you exactly which search engines it gets results from at the top of its results. Timeouts can reduce the number queried, and there's no way to increase the time limit. You can at least control exactly which search engines are queried via the Advanced link, found next to the search button, on the Search.com home page.
Paid links were not identified as paid content, either in the main results section or in the "Search Partners" area
ProFusion doesn't show you exactly which search engines it queries. By default, AltaVista, Excite, LookSmart, MSN Search and Yahoo are selected. This can easily be expanded by using the advanced search link from the ProFusion home page, and you'll need to do that if you also want to get FAST/Lycos results and Open Directory information from either AOL Search or Netscape Search.
No paid listings are mixed with the web search results. Paid listings from GoTo do appear in the Search Partners area at the top of the results page and are not identified as paid links.
qbSearch is like Dogpile. It stitches the results from various search engines together. qbSearch also lets you easily choose exactly which search engines you want before performing your search. However, by default, it will search at only five services. Only two of the services are important editorial sources: AltaVista and Yahoo. The remaining three services provide paid listings. Paid listings all had some type of identification shown next to their results, such as "bidded listing" or "cost to advertiser."
In other notes, Yahoo is listed as Yahoo/Google. This is because some Google results are available via its partnership with Yahoo. However, these only appear when performing very specific queries. Also, though there is a "Lycos/HotBot" option, these only brought back results from HotBot.
Meta Search Survey