Studies show that the majority of Web searchers enter extremely simple queries, so a reasonable system design approach would be to build search engines to compensate for this user characteristic. One hundred representative queries were selected from the transaction log of a major Web search service. These 100 queries were then modified using the complex search operators supported by five major search engines. Overall, 1900 queries were submitted to five Web search engines, returning 18,256 documents. The results obtained using the complex queries from each search engine were compared to the results obtained by the original 100 simple queries from that search engine. In general, increasing the complexity of the queries had moderate effect on the results, with an average 66% exact match between results from the simple and complex queries. Implications on the effectiveness of current Web search services, for future search engine design and for future research are discussed. (Contains 23 references.) (Author)