There is in fact a vast amount of prior art, and I've been baffled that such attempts to assert such a patent can get any traction at all.

The full text of the patent can be found here on the PTO Web site. Ironically enough, the page uses the patented technology to display the patent.

The patent covers the idea of client-server computing, in which a central server performs "computation" on behalf of a remote client, such as a personal computer running a Web browser. The patent gives examples from image processing, but they're only examples, and claims that "other applications are possible". Yeah. Like the software that runs this BBS! Like most patents, it's written to leave the door open for the broadest possible interpretation of what it covers. From this basis it's possible that damn near every use of clients and servers could be argued as infringement.

There's nothing new about the idea of client-server computing. It has deep intellectual roots, and it could be argued as well that even the dumb mainframe-terminal systems of the 1960s were client-server systems, since the mainframe performed computations at the request of commands entered into the terminal. Looking narrowly at their examples from image processing, graphic terminals came along in the late 1960s to display images created on mainframes. NASA pioneered much of the technology during that period.

Here's an outline:

In the late 1940s, FDR's science advisor Vannevar Bush wrote a paper called As We May Think setting forth his thoughts about using emerging technology to build a global knowledge base which would make all of humanity's knowledge accessible to everyone. His specifics have, of course, been superseded by actual developments, but in essence he foreshadowed the concept of the interconnected Internet and search engines which implement his vision.

In the early 1960s, Ted Nelson began studying the problems of handling text in electronic systems, and around 1965 he coined the term "hypertext" in a paper presented at the annual ACM conference. That concept alone, to me, represents a profound prior art that describes the act of browsing the Web. Ted had the chance to try to put his ideas into practice in 1988 when Autodesk sponsered Project Xanadu to build what we would recognize today as the Web. I was a consultant at Autodesk around 1990 and had the chance to read internal papers about it and follow their work. Xanadu was eventually abandoned as unworkable (prohibitively expensive to build), but I think it was just ahead of its time. They were trying to build it all themselves, while the Internet evolved organically through the efforts of thousands of people and the connection of millions of individual computers. [Ted Nelson's biography]

There were other early intellectual threads feeding into the development of the modern Web. According to <a href="http://www.walthowe.com/navnet/history.html>A Brief History of the Internet:

The Internet was the result of some visionary thinking by people in the early 1960s who saw great potential value in allowing computers to share information on research and development in scientific and military fields. J.C.R. Licklider of MIT, first proposed a global network of computers in 1962, and moved over to the Defense Advanced Research Projects Agency (DARPA) in late 1962 to head the work to develop it. Leonard Kleinrock of MIT and later UCLA developed the theory of packet switching, which was to form the basis of Internet connections. Lawrence Roberts of MIT connected a Massachusetts computer with a California computer in 1965 over dial-up telephone lines. It showed the feasibility of wide area networking, but also showed that the telephone line's circuit switching was inadequate. Kleinrock's packet switching theory was confirmed. Roberts moved over to DARPA in 1966 and developed his plan for ARPANET. These visionaries and many more left unnamed here are the real founders of the Internet.

Around the time of Xanadu, in 1991, the "gopher" Internet protocol was invented. This is the first specific implementation of a hypertextual system on the Internet. It was primitive and oriented toward use on dumb terminals--it was pure UNIX--but it really was hypertext.

Tim Berners-Lee began work on the protocols that would become the World Wide Web around that time. In 1993 he introduced Mosaic, which later became the basis of Netscape, and the rest is familiar history.

There's more prior art outside the sphere of the Internet. After cheap personal computers became available in the mid 1970s and cheap 300 baud modems came along, people began setting up bulletin board systems, the first "BBSes". It wasn't long before BBS operators formed alliances and began interconnecting their systems, forming their own primitive "web". AOL has its roots in those first BBSes, and along with Prodigy pioneered the very first GUI front ends. I would expect there to be much prior art to be found there.

As I recall, Lotus Notes didn't come along until around 1988, so it probably is not the "headwaters" of prior art by itself. I'd look at the ideas that influenced the Notes developers at the time.

There is prior art from Microsoft, too. Windows 3, introduced around 1990, contained an online help system with hypertext links. Since the lawsuit is directed at Microsoft, I have to assume that they'll be pointing that out.

The stupidity of the Patent Office never ceases to amaze me. They award some of the most ridiculous patents for things that are well-known to those with a clue about a particular field. Their defense is that they're underfunded and understaffed, which is plausible given the cost-cutting mania of the last decade and a half. But considering the economic havoc they wreak with bogus patents, it sure as hell would be cost-effective to fund them adequately.