Fotiman - 1:07 pm on Oct 14, 2010 (gmt 0)

Yes... as I said above, this value only gets changed when you make changes to the file and want to force the browser to pick up the new version. So developer creates version one of the file on, say, October 1st and the HTML has a markup like this:

<link href="style.css?ck=0.656089390631731" ...

The browser will recognize that it hasn't fetched this file with this query string, and force the new download (where it may cache it again, so future requests using this same querystring use the cached version).

That remains unchanged until the developer makes a change to the CSS file on, say, October 14th. He/she wants to make sure browsers don't continue to use a cached version of the file, so the developer changes the link in the HTML to something different:

<link href="style.css?ck=0.656089512885179" ...