I surf the Web from many different computers, and therefore I can't effectively use the "Bookmarks" feature of Web browsers. So, I decided to put my bookmarks collection online and to manage it from the Web. This way, I will have my Internet bookmarks always at hand, everywhere I am (assuming I have a net connection, of course!).
I decided to use the XBEL format, which happens to be the native format of my favourite browser (KDE Konqueror for Unix). For a start, I copied the file containing my bookmarks onto my home page. Then, I needed a PHP script to format the XBEL file into a nice HTML; I was lucky, because Roberto Giungato had already written it. I took his script and modified it a bit to better suit my tastes.
Eventually I gave up, because I still had to implement the edit functions and the XML support of PHP wasn't complete yet (for instance, there was no standard DOM parser).
I installed the ol'bookmarks software; it consists of a set of PHP scripts which interface with an SQL backend where the bookmarks are stored. The obvious drawbacks are that it requires an SQL server (for which I had to pay extra to my ISP) and its native format is not XBEL; however, the software is well tested, it has every feature I need (plus some more) and I even wrote a function to export the data to XBEL format. Excellent! This is the system I'm currently using.