There's something about this link exchange that I want to tell everyone about. Those of us who got started with it before the Great Crash of Aught Six know the history, but, like so many good thoughts, it's gone.
There has been some concern whether using the PHP script will really help you, as the list of links is hosted on our site. On the surface it would seem that we (Squier Photography) would be helped the most because everything would be linking to us -- including the links list on your sites. This is not the case. In fact, it could be argued that we helped many more people with the exchange than helped us, as we were very highly ranked to begin with.
This is how it works: The PHP script uses a Server Side Include (SSI) to grab the list from our site and put it into the page on your site. The key word there is "Server." Your Web server is going out and getting the list, then it, in turn, is "building" your links page as the page is requested. So, to anyone browsing (or spidering) your page, it looks like everything is on your server.
There are ways, using the
browser, to "include" Web pages into your links page. These can be frames, iframes, and using Javascript (not to be confused with Java, which is totally different). The way these "browser-based" files work is your Web browser "asks" for the page, sees that there are parts that come from another site, and then display the page. The browser
knows that the "other parts" are on another server. If this link exchange were set up this way, no one but us would see any benefit (except for those manually updating their lists, of course).
So, because it's a
Server Side Include, you reap all the benefits.
There are some hosting companies that don't allow external server side includes -- that is, getting include files from other servers. If your hosting company doesn't allow them, you won't be able to use the PHP script and must update manually. The reason they don't allow them is that it's possible for someone (me) to put "bad stuff" on the include file and create a security issue on your site. While this is possible, people trust me not to do that.

Not only that, but most hosting companies have other security measures in place so that even if I were to "go anarchist" on you, nothing bad would happen.
I hope this clears up some of the confusion.