Bad News

• The http protocol is stateless --
  • Makes the web simple to administer
  • Makes it hard to build useful, realistic applications
  • Much programming is needed to remedy the shortcomings of http, i.e. to capture, manage, and retain state ("session") information
  • Simple protocols are a blessing and a curse.

• Caching is a mixed blessing --
  • Done by proxy servers and by browsers
  • Improves performance, saves bandwidth
  • But cached, out-of-date documents can deceive unwary users
  • E.g. you cannot prevent a user from clicking the Back button to return to -- and attempt to use -- data that's no longer valid (deleted or updated).
  • Document header fields can disable caching... but then the browser can't print... gotcha!

• Forms are the basis for web-based user interfaces --
  • Not adequate for building sophisticated UIs

• Each server has limitations, e.g. CERN can't do server-side includes, NCSA can't proxy, IIS is excessively bound to NT, e.g. stores user and password information in the registry, hence is ill-suited for high-volume websites

• Lack of standards for advanced features such as Netscape's Javascript and Microsoft's JScript.

• Proxy servers reduce the usefulness of server logs and hinder accurate accounting of Web usage.

• Document caching improves performance but can fool unwary users with obsolete data.

• Network bandwidth bottleneck -- the "Worldwide Wait".

• Hand-editing raw HTML is difficult and unproductive but many web authors find little productivity gain from the current crop of WYSIWYG authoring tools