commensalism
"Commensalism is like giving a ride to someone who is on your way to your destination. The person you pick up definitely benefits because he doesn't have to spend money on gas or even find his car keys."
"An example of commensalism is like the relationship between the sun and the plants. The plants benefit from the sun's sunlight, but the sun does not benefit from the plants, nor is it harmed by the plants."
"Commensalism is like a fish hitching a ride on the shark. The fish gains from this by expelling less energy to go farther, while nothing happens to the shark."
METAMIA is a free database of analogy and metaphor. Anyone can contribute or search. The subject matter can be anything. Science is popular, but poetry is encouraged. The goal is to integrate our fluid muses with the stark literalism of a relational database. Metamia is like a girdle for your muses, a cognitive girdle.