Thanks Mike, I still don't understand most of the differences, but I was able to get what I wanted. I went into page size, made it custom by points, made it an arbitrarily large number of pixels (i.e. 2000x3000), then zoomed so the full layer was in the data view window. I then went to layout view, export map, chose a low dpi (94), exported, and it came out as I wanted. What I had been trying to do before was export a letter-size page at 300 dpi, instead of changing the resolution of the page itself. Thanks again! Yknow, since you work for ESRI and all, you might want to tell them that I went through the entire Teach Yourself ArcGIS from ESRI Press and did not find that concept anywhere.
Glad that you got it. I always start with a layout size that is planned before hand. this usually saves me time. I rather get it down close to final, so I don't have to go back into it and fiddle with scale, line widths, symbol sizes, text sizes, etc if the image size changes.
If you are aiming to show your work for on screen purposes, just do your exports at 72ppi. that is a good compromise and is historically (early Apple history) the screen resolution of monitors. it's a good measure of what you will see at 100% on screen. if you are aiming for print, 300dpi is pretty much standard. you can always go higher, but large scale printers usually downsample back to 300dpi b/c to the eye, anything larger than that is not a huge noticeable difference. if you have Adobe Photoshop, play with the image resolution and size settings to see what kind of results you get.