I am making a logo for a friend and I want the text to have a gradient. The gradient shows up in the node editor and the material view, but not in the rendered view. What am I doing wrong?
A shader is the function that describes the lighting interaction at the surface or of the volume. That is different from the color of the surface itself.
A red carpet's surface is still of the same shade of red even in a dark room, we just perceive it dark because there is no light around.
At the moment you are defining only the "color property" (yellow socket) of the surface, but not how this property should interact with light. You shoud use one of the nodes you can find under the "shaders" menu. It will acquire the color data as input and output a shading data (green socket) that should be connected to the Surface's socket of the MAterial output.
You need to add a Shader node between the Color Ramp and the Material Output - in your case probably an Emission Shader. As a general rule you should typically connect sockets to the same color - in your case you have a Color (yellow) connected to the Surface (green). You should only ever connect the output of a shader to the green sockets of Material Output.