On Thu, Oct 19, 2000 at 12:28:04PM -0400, Daniel Senie wrote:
It might be worth thinking about the problem from the other end. From a web site owner's perspective, caching is a major annoyance. Here are the arguments you may encounter from a web site owner or web developer:
Agreed. It's an annoyance. It could be considered a cost of doing business...
1. It interferes with content in many cases (web site visitors may see cached pages instead of current content). I know cache products claim this doesn't happen, but it has, and often.
Then the content probably needs fixing. (eg with caching primitives)
2. The website owner loses information on how many visitors are coming to the site.
Then the content probably needs fixing. (make the smallest object uncachable, perhaps with use of caching primitives, an empty cgi, a bit of javascript etc)
3. The website owner loses the demographics on where visitors are coming from, and especially the number of unique visitors. (It's not helpful to know that one cache engine visited, if that cache engine equated to 10,000 visits in an hour).
Sometimes that's just tough luck (some people use caches/proxies to protect their own identities). Other times the content could be fixed (cookies. ugh.)
4. Banner advertising may or may not display properly when caching is involved, thereby costing the website money.
This is an orthogonal problem. The website owner doesn't control whether or not caching is involved so she should pay more attention to making sure that the banner advert is done in a way that works in either case! The secondary issue of needing to know when banner ads are seen... well, maybe the content could be fixed to help that too...
5. There's NOTHING in it for the website owner, other than the possibility that SOME pages might display faster for SOME users.
Don't website owners pay for bandwidth anymore? :-)
If folks running networks really think website designers and owners should care about caching, then there needs to be some sort of benefit (perhaps paid in dollars) to those affected. Otherwise, there's little reason for them to care.
Some website owners need to remember that some Internet users don't use a cache/proxy out of choice, but because their ISP forces all (web) traffic through it. Not taking caching into account when designing a website is fine if the website owner knows the setup that all her customers will be using (like an internal corporate website), and it's fine if the owner doesn't want all those things you mention to work with all the audience, but it seems like a silly idea for -this- Internet. Regards, Andrew -- andrewb@demon.net