Continuing on the theme of not-immediately-obvious ways in which the net moves information, have a look at Terra Nova: Automated Expertise Management. This tells the tale of Thottbot.com,
At first glance, Thottbot looks like a normal third-party MMORPG information site. Try searching for “Fiery Enchantments” – a lvl 42 quest in the game. Thottbot has the details of the quest stored. But imagine I just picked up this quest and I don't know where these “dragon whelps” are that drop the “black drake's heart”. If I follow the “black drake heart” link, Thottbot shows me all the mobs that drop it, their level ranges, and most importantly where to find them. Click on the “map” link next to the lvl 41 Scalding Whelp. Thottbot dynamically generates a map of the zone where these mobs are found and their spawn range. All items, quests, mobs and maps are cross-referenced in Thottbot.
Now, you might think that Thottbot has this information because of constant submissions from good-hearted players (which is how other sites do it), but that's not what's happening. There is a free custom GUI called Cosmos which allows customized toolbars as well as mods that add functionality. Of interest to us here is that Cosmos also sends information (optional) to the Thottbot database from every player who uses it. Every mob, item, quest and player character that is encountered has their stats and location tracked and sent to Thottbot automatically.
In other words, the expertise of individual players is automatically tracked, stored and shared by the system. More importantly, the aggregation of their expertise allows the discovery of what would otherwise be hard to know – the spawning ranges of mobs, the drop rates of rare and uncommon items, and so on.
It's not that hard to imagine how this gets generalized to other types of online activities within structured settings…maybe google searches, ebay bidding strategies, or comparative shopping. It's somewhat harder to see how this helps me outside structured action/query-response environments. But if it did…