For example, Expedia (and other hotel sites) have alerts that come and go that say things such as, "17 people have booked this hotel this week." Is there any documentation out there concerning this practice?

Interested in reading more about this and what kind of impact it has on users and interaction with the site.

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    I can only think that this helps build urgency in a users mind. "All these other people can make up their mind. What's wrong with you? Just book it already!" In my work context, we are designing this sort of activity alert in our product to help users determine best practices. ie. 15 users ran this report today, or, 32 people have this widget on their dashboard. But I'd like to read some studies when there are REAL dollars on the line if you can encourage a user to act now.
    – drawtheweb
    Commented Jan 24, 2013 at 21:02
  • @drawtheweb that doesn't show best practices, that shows most used practices, the 'majority' don't always know whats 'best' and whats 'best' isnt always used the most.
    – user25512
    Commented Apr 17, 2013 at 10:12
  • @RhysW: True, just because everybody's doing it, that doesn't make it right or best. That said, knowing nothing about drawtheweb's particular project, it's certainly possible to use social proof to encourage "best practices" within a given community. Seems to me like an interesting challenge ... of course, that doesn't mean the design will generalize elsewhere. Also, we have to believe in the wisdom of the crowd to some extent, don't we? Is something "good" because 100 people like it, or do 100 people like it because it's "good"? Who's to tell the majority they aren't "right"?
    – in_flight
    Commented Jan 16, 2014 at 13:50

1 Answer 1


I believe this is 'social proof' phenomena. Basically, people are more inclined to buy something or perform actions if they believe that other people have done the same. It gives them confidence and a belief that their actions are 'approved' by other people.

A nice experiment is summarised in this paper:

In the elegant experiment described in Salganik et al. 2006, researchers constructed an online music market and examined the role social influence played in which songs participants chose to download. The experiment revealed that increasing the extent to which participants were able to observe the selections of others [...] led to an increase (decrease) in the popularity of the most (least) popular songs and a decrease in the predictability of song popularity based on quality.

In other words, by showing the "number of downloads" statistic, users' perceptions of quality changed and they were more likely to download music if it was downloaded by others.

Other examples of social proof include product ratings on Amazon, customer reviews and number of upvotes on this question/answer.

Interestingly, it's also suggested that queuing for a product increases its value -- perhaps being the first to do something gives people a euphoric feeling, hence why "n people are viewing this right now" could be encouraging (this is my guess).

This is a very clever trick that Expedia is using, and has certainly made me think about using it in the future.

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    Would be interesting to know how many sites are actually honest. I've never seen one that says '0 are doing this' etc, when you know that at 1am in the morning for some obscure b&b thats had a website for a week, definately isnt getting collectively 50 bookings in the last 15 minutes!
    – user25512
    Commented Apr 17, 2013 at 10:17
  • "...people are more inclined to buy something or perform actions if they believe that other people have done the same." I'm not sure that applies to the booking and reservation practice of displaying reservations left. It is informational, not a sales technique. Commented Jan 16, 2014 at 10:32
  • Interestingly enough, airplane ticket sites like Kayak don't technically need the "finding ticket prices" progress bar at all, (like this: puu.sh/6n2mP/ff73f701cb.png) since servers and computers can do all those calculations in less than a blink of an eye. However, on a UX stand point, the fact that you have to wait for your results gives you a sense of anticipation and reward. Commented Jan 16, 2014 at 17:12

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