Before Google arrived with their efficient popularity ranking we were lost. Web content grew bigger and regular text indexing search engines delivered us huge "unordered" results per query that made us click and click endlessly.
One way to measure the effectiveness of a search engine except for a good personal sense of effectiveness is to track the time or the effort being put by the user (amount of clicks and other helper searches that users are required to run in order to reach their desired content at the end). Looking at this criteria we can see a dramatic decrease following Google adoption, a decrease that resulted in much less searches or "page next" clicks.
This gap between the moment a person decides to look for information on something he or she is interested in to the moment the desired information is found still remains wide open (the search interaction gap). Google as the current leader in narrowing down this gap invented few very effective "tricks" such as Google correction mechanism, high response time (easier to navigate to next pages this way) and user accumulated expertise in search engine intricacies (how to query "right" the search engine).
The main problem today behind this search interaction gap is the match between a person that is interested in something that is unique and "non-visible" to todays' search engines with their "naive" search text boxes were users are expected to "flatten" their information interest or thoughts to a plain "machine understandable" text query. This responsibility being set aside on the shoulders of users does relieve temporarily developers from devising new ways to deliver information, a "status quo" between SE developers and users that is based on an underlying assumption (and wrong I think) that people know how and what to search.
The blogosphere added additional complexity to this already complicated relationship between users "inner" interests and the level of service they get. The blogosphere thanks to the permanence of its content behaves also as a knowledge base and users interested in blog related material have few new other interests that didn't exist before blogs came along. Social software have also contributed in narrowing this gap thanks not to some technological miracles but rather to the connectivity it created with other people that might have a better lead to what you are interested in.
I see this "search interaction gap" and the goal of narrowing it down to minimium as the ultimate purpose of every search engine or information access tool, which is to provide what the user needs in the shortest and least resistant path.