A recent thread on the Summon discussion list has spurred further discussions elsewhere. The thread started with a complaint about the lack of predictability among the results of boolean searches in Summon. Essentially, it was hard to determine why particular results appeared in the list due to other "relevance factors" that "polluted" the ranking of the results. The librarian mentioned having a preference for "the pure drop" - predictability. From this initial comment, other discrepancies of results of the same searches in different systems, notably relating to differences in processing boolean operators, stemming, and phrase searching. This led to additional posts calling for "advanced" search functions, such as proximity operators, wildcard (or "hard stemming"), and search set manipulation, all of which could be described as "librariany". The thread was pretty much ended by the comments from the other end of spectrum - those who were concerned that such changes would revert the Discovery system back to a typical library database. These posters pointed out that such systems were purposefully designed not to be like your typical library database - built for the easy use by students and non-experts, not for the librarians.
This thread was picked up by Aaron Tay, Senior Librarian at National University of Singapore. He started thinking about the effect Google and search engines in general have had on library databases, including catalogs and abstracts & indexes. He considered how such systems have slowly adopted selected features and functions that users have come to expect in any search engine of any kind, notably ranking by relevancy, "implied AND", automatic stemming, and full-text searching (when possible).
As he discussed the implementations of these features, I noticed that predictability of search results is a common thread of concern among librarians. We want to explain why each and every result is in that set. We want to be sure we get "the pure drop". This is an essential difference between librarians and the clients they serve. Students do not appear bothered if there are a few irrelevant results - as long as they get more relevant ones than not. They effectively "bleep" over them and move on. Furthermore, for most students and public library users, the level of satisficing is lower than for librarians and some expert searchers. These attributes may explain why our users (and many front-line reference librarians) love these Discovery services so much more than expert reference and research librarians.
In my view, Summon has done well to bring more resources to the attention of our users - full-text usage is up, as well as audiovisual downloads. The expert searching features and functions should only be introduced if they do not interfere with the system's core feature - a simple keyword search interface. Certainly, I agree that they should not "treat it like the 'normal'" library database. There are different tools for different tasks - choose wisely.