Q:

Pagination: Let the user choose how many items are shown per page?

Does it make sense to let the user chose how many items are shown per page? Or does it make sense under certain circumstances? When? When not?
This is how some big websites handle it:

Google: Used to be in advanced search, doesn't work with Google Instant
Bing: Can be set in preferences
Amazon: Nope
Ebay: Yes, looks like this:

My Impression is that this is a remnant from the old days when the number of items had a real impact on the loading time (so you would generally have it low and allow users with more bandwidth to set it higher). But many people I talked with want to keep the feature. Any thoughts? Pros and cons?

A:

I think pagination is another one of these cases where a good default value makes all the difference, and - as Amazon and Google show - it's then even possible to keep the burden of choice from your users altogether. 
In my opinion, a selectable value for the number of items per page really only makes sense if that one page contains multiple conflicting requirements - e.g. providing the user with a quick overview over lots of data and showing lots of details of single data items without overwhelming the user. 
In this case, an underlying problem may be that the purpose of this page is not clearly defined.

A:

my personal choice will be to eliminate the concept of item per page and also get rid of the concept of pages.
just display all the items that fit the current portion of the page the user see. then auto paginate (autoload) the rest of the result as the user request them scrolling down (like facebook loads older posts).
I'm rewriting an application which had pagination of datagrids and a user configurable "item per page" value. Now the new application only have "infinite" auto pagination linked to the scrollbar. the feedback is very positive till now.
regards.

A:

User-defined pagination seems right to me, at least in the context of tabular data. 
For instance, consider the tables in Google Analytics: 

I presume many would find the table of data less user-friendly if 
you weren't allowed to set how many rows should be displayed.

