One could even go so far as to make a case that the single most important feature responsible for Mosaic's success was the integration of "in-line" graphics with the page. Looks count.
Web browsers are starting to natively support more image formats, inline. However, helper applications are still necessary, and will be for quite some time.
One popular "Knowbot" is the CNRI "Knowbot Information Service," which helps you find email address located at: http://info.cnri.reston.va.us/kis.html.
For a good overview of this rapidly changing domain, check out the book Frontiers of Electronic Commerce by Kalakota and Whinston (Addison Wesley), 1996, or the Web site at: http://commerce.ssb.rochester.edu/book.html.
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