Greg Notess reports in Online that Yahoo! no longer has full support for Boolean.

Boolean is a search syntax used for composing more complex queries in search engines. (See out Goalgetter tutorial for an introduction).

Now the NOT operator is gone in Yahoo!, and searchers will have to stick to the “search engine math” operator to achieve the same effect. Put a minus-sign directly in front of a term that you want excluded from search result (meaning that Yahoo! will exclude pages that has that term in their text).

Yahoo! has also dropped support for the AND operator. This is not equally serious, as Yahoo! will do an AND search by default.

The OR operator still works, but nesting with parentheses fails.

Yahoo! has apparently come to the conclusion that since so few uses Boolean anyway, they may as well not support it. That is a mistake. Power-users like librarians, journalists and researchers use them, and they are exactly the kind of people that influences the public opinion in these matters.

Bring back Boolean, Yahoo!

Google still accepts the most popular Boolean terms, and Exalead even supports the NEAR operator. Still, as Notess says: “Live Search is now the only major search engine with full Boolean support.” Hm. Interesting. In this area Microsoft is the search engine winner!