Besides the information on this article there's also a lot more information on how to reduce your bill and serve your site way faster on this one > http://news.ycombinator.com/item?id=352695

You also get a big performance boost when you use the cache-control headers properly. Because you'll be saving the browser having to connect to the server to check if the file changed, and if you have many js, css, and image file, then you'd be saving a lot of round-trips.

I thought the point of a web startup is to figure out ways to increase your hosting bills... :)

AFAIK, one of the browsers (probably IE), ignores query parameters on css and js files and will not refresh foo.css?v=2 if it has foo.css?v=1 in its cache.

I've never seen this behavior anywhere.

I am told by someone with a high volume, consumer site that there are proxies in use that strip the query parameter from URLs that they guess are images. They are rare, but they caused him to put the serial number in the file name. (This was several years ago, I don't know if these proxies still exist.)

Facebook would probably confirm that this still happens. They switched from simple ?cachebreakers to:

http://static.ak.fbcdn.net/rsrc.php/zD9BP/lpkg/rjg2jdf2/en_U...

Thanks for posting this, very useful.

One of our services relies heavily on S3 for image storage.

These tips are definitely useful for S3-based apps, but are also very informative in general. Thanks a lot for the article.

Great article.