A lot of product photography is composed of the object itself superposed over a pure white background. Now, some may think that the background in actually shot pure 255 white and, in most cases, it isn't. There are a few ways to photograph something for a white background. What I do is a put a sheet of Savage Translum (translucent plastic) directly behind the subject and fire a strobe behind it. I always make sure that the background isn't pure white because the edges of the product can get blown out, flare and disappear. Not appealing. I prefer to cut out the product in Photoshop and replace the backplate there.
So, I need to have a way to measure the light intensity at the background. Fortunately, Capture One Pro makes that dead easy. Just move your cursor over the area that you want to measure and the software will give you the readings for each colour channel (R, G and B) at the top of the frame. It also presents you an average value. I always try to keep that one around ~242-247 depending on the photo. Also, you can check that data in Photoshop in the Info panel. If you don't see it, head to Window and choose Info. From there, it works the same way as in Capture One.
To me, it's very important that I don't blow out the background whilst shooting and these tools help me keep an eye on that.