Out of 7 interviews this year, only two involved a job talk.
Last year, nearly all of my interviews involved job talks, even for positions at research institutes that would require me to set aside my own research until I got my own grants, tenure-track at a regional commuter school whose courseload was too high for research, and visiting faculty at an elite small college where the faculty guiltily confessed to me that they had just about given up on their own research. In one case, they didn't even have a position for me, but the department chair for the field I have my MA in was very friendly, the university is rapidly expanding and my field will eventually have openings, and I was in the neighborhood, so they brought me in and I gave a talk and had lunch with the faculty; that was my favorite interview, perhaps because it wasn't an interview, and I got the career advice that has influenced me the most.
I took for granted that all interviews include job talks. Jobs without an interview process didn't have job talks, of course. Two postdocs gave me an offer without meeting me, and my current postdoc came about by accident; naturally, none of these involved job talks.
This year I have realized that I should be prepared for a soft-money environment, so I have focussed my search to postdocs in well-funded fields which will teach me how to apply for grants, and it's been a surprise to see how few have job talks. The two interviews which asked me to give a job talk make me lean so much more towards them --- should I get an offer --- because they show that they respect me as a researcher. The fact that some places skip job talks also made me realize how much trouble they must be for the department, especially the ones which get a huge audience. My December job talk had an audience of over 40, and this was close to Christmas-time.
My best interviews last year, such as my one tenure-track with an elite college, had a huge audience; I even got a DVD to show my parents.
Meals are also a sign of interest, especially when they can get a few prominent faculty or many people to show up. Nearly all of my interviews last year involved at least one meal with faculty, but the postdoc interviews rarely have much of a meal. So far, I've had pizza with RAs, lunch at a food court and being allowed to tag along at a fancy dinner with a visiting speaker (clearly, the reason for the dinner), and two small catered lunches with faculty (one of which included another candidate!); two had nothing. The food doesn't matter as much as who they get to come. After my December job talk, I had tuna salad with the most prominent faculty, including a woman who must have been 80 years old, whom even some of the younger faculty at the lunch had never met; she asked a lot questions and really seemed to care about my research; that really impressed me!
The interviews which have at least 3 hours of interviews, a job talk, and a meal are exhausting, and I know that they are extremely time-consuming for faculty, who don't manage to get anything else done during interview season. At the same time, by making this kind of effort, departments get to signal that they (1) care about the research of emerging researchers; (2) want to enrich their department by sponsoring a talk, which many departments don't have many of; (3) see postdocs as a citizen of the department, rather than serfs in academic feudalism.
The extreme opposite is signaled by being the interview that I declined: 45 minutes with person A, 30 minutes with person B, and a phone call with my mentor-to-be who doesn't even live in the city, so I would never see them after starting the job.
Now off I go, to try to find more postdocs that will have lunch with me and have me give a job talk.