The buzz-word of the week is "mash-ups." The first time I heard this term was in reference to music mash-ups where someone takes two or more popular songs and spins them together to create a Frankenstein mix.
"Love in an elevator" + "Yellow Submarine" = "Love in a yellow submarine"
...Or something like it. The actual music is much better and there are some real gems.
The second type of mash-up has been the Web 2.0 type of mash up where someone takes two websites that provide API's and brings them together to provide a website mix of both worlds. The most common example of this is HousingMaps.com that combines CraigsList and Google Maps.
Why is this exciting? It's now possible for anyone to stand on the shoulders of giants. If you have a great idea you can build it and you don't have to reinvent the common infrastructure of eBay, amazon, Google or others. You can use their infrastructure and in turn make their product better as well.
Why data hyperlinking? So far a hyperlink has been just a pointer to a different place where the information exists. The new hyperlinking is actually pulling down the information and integrating it with your own concepts. Mash-ups also represent a fairly non-restricted use of the the new style of hyperlinking. Similar to normal links you currently don't have to ask permission, sign an agreement, consult a lawyer to use these new links. You design and create your own vision and use data hyperlinks as you need them.
It's possible even perhaps likely that some mash ups (music) will be attacked by certain lawyers but for now it's the wild west. From the website standpoint it looks like web-mashups and data hyperlinks are here to stay