Something very significant happened with Google's promotion of its Keyhole acquisition. Keyhole had taken a new approach to GIS (geographical information systems): they created a fast intuitive interface and they made the technology relevant to consumers (not enterprises) by making it a fun exploration tool with a strong sense of grass roots community. You didn't have to have any goal in mind to get value out of the tool. Google then came along and used its mega-brand muscle to get this technology to a huge user base. One could debate whether the inclusion of local search and directions impacted the hype and excitement that was generated.
To put it in perspective, the Google mapping buzz was in the ballpark of that for the launch of the Sony PSP, a major event in the huge handheld gaming industry:
Shortly after its launch, Sony sold somewhere in the region of 500, 000 units.
There has been some discussion in GIS circles that this was a missed opportunity for the major GIS firms (particularly ESRI). However, the consumer market has never been the focus of these corporations and so the opportunity involves a huge consideration wrt user support, deployment, server infrastructure and so on - something which a major search engine is swimming in but which enterprise software vendors are not.
Ok, now given the above description of Google's impact on GIS, what other technologies will be popularized in similar ways, how will the be made relevant to consumers and how will they impact the search space. Don't forget, Google Earth is a departure from Google's simple light weight interface.
I see this as breaking down into two broad categories. Firstly, there are those technologies which will give greater power to the user but not change the search interface significantly. Take the area of corpus annotations. Imagine being able to search for nouns, verbs and combinations of these. That would be immensely powerful. Secondly, there are those technologies that would require a departure from the the generic search interface. Specifically, I see the potential for a number of technologies that deliver analytics. Imagine if Google provided trends over spans of text that accurately identified person names, or product names.
This second category is where I see the world of online personal media (OPM) portals as being trailblazers. The most obvious example being blog search and analysis engines. The reason for this is that the volumes involved, in terms of posts, is huge (giving a user similar experiences to web search in general and making data driven analytics such as trend mining meaningful), but there is a very strong constraint in terms of the type of document that is covered (simple and generally short messages, most often created by a single author) and, importantly, there are very clear meta data which users can understand (comments, citation links, trackbacks, etc.).
Bringing these things together has the potential to generate a huge shift in user expectations and behaviours when it comes to how they interact with online data. The hardest part about moving forward with search is not the existence of powerful technology, but the popularization of that technology in a way that can alter consumer behaviour.