As the information is being retrieved, the user can even have the information filtered. For example, the keywords can be bold-faced so that they stand out when browsing through the results. Similarly, the user will be able to specify the number of lines of leading text returned before the matching string, as well as the number of lines of trailing text returned after the matching string. At this point, someone may be questioning if users commonly terminate retrievals after a short wait, why would they tolerate one longer wait. The answer to this question involves an understanding of the difference between response time and turnaround time.
Response time is the elapsed time from submitting a request to receiving the first response.
While ideally response time should be 1 second or less, on the web users have been trained to endure response times as slow as 10 to 15 seconds. On the other hand, turnaround time is the elapsed time it takes for the entire job to complete. Typically there is no maximum time limit associated with turnaround time, since it varies directly with the task being performed. Our experience indicates that users will tolerate a longer search turnaround time if they feel the results returned are more complete and the relevance of the results can easily be determined. Search multiple databases Search engines such as WebCrawler often fail to warn users of the limited resources which their databases have indexed.