Like any mother who can hear her particular child calling "Mommy" through the din of a noisy children's room (and it gets really noisy in here), I've noticed my own somewhat attuned "ears" based on patron/friend requests that come my way*. To some degree this probably drives my friends nuts--if I see something on or related to a recent topic of discussion or an interest of theirs, I shoot an email that rarely says anything other than "thought you'd like this-Abs. [Hyperlink]" But at times I'm told it's helpful.
It's a skill that can bring a lot of value to a patron/friend, especially if that someone is willing to work with a librarian and who has an ongoing research project.
Point in case: last fall, in a fit of what-was-I-thinking, I took on an intense short term research project for a former editor of mine. The deadline just happened to be the week before I moved out of Chicago. While we squeaked in under the deadline her particular subject (veteran medical care, particularly trauma that may not have a clear physical manifestation), this is obviously a topic on which material is still being published. So while I skim through the endless RSS feeds that pour in each day, if anything has her particular keywords (or looks appropriate), off goes an email. Though often these are just archivable supplemental material, it meant last week that she quickly saw the new change in the Disability Rating Schedule for Traumatic Brain Injuries (Thank you Docuticker!!!). She was thrilled to get that email.
Of course, a lot of this is patron/subject specific. I'm in a public library working with children. As a result, at present I have a better hold on what new ya novel might be fun for a middle school girl (Confessions of a Triple Shot Betty--Jody Gehrman), what easy chapter books a mom with a young princess-obsessed girl might want to grab for bedtime (Vivian French's Tiara Club series), and just where the big set of color-themed picture books are (P* SCH) than I do on the most recent military histories or cookbooks or changes in real estate law but that can be said of anyone working with a specific type of patron. But certainly your "ears" can change over time, just as a mother might have to adapt to a) her child's voice as it grows and b) a new child, a librarian should be flexible enough to grab different subjects as patrons change.
It's a convenient filter to have set for the researcher though, one I could see particularly useful in medicine, law, or academia in general. If you have worked with a librarian who is in contact with resources on your subject every day and they know what your current project is--might they be not more likely to send you the latest and most fabulous new article to help you? But I preach to the choir.
As my ears go off again though whilst I scour my feeds, know that I forward you that 50th link to DC comic art showing all of the women of DC Comics not because I'm trying to flood your inbox. I've just developed strong Librarian Ears.
*Note: This particular type of ear is different from those ears that pick up on children crying for reasons other than it's time to leave the library or vacate the computer, can hear a curse word at 100 paces in the children's room, and have a keen sense of awareness when tween boys are gasping over a website that probably shouldn't be opened here.