Netflix is testing out commercials for their subscribers. Not everyone is getting this feature - they are testing out for selected viewers to see how people are using it and so forth.
The commercials are related to Netflix shows like suggestions of things to watch or previews of what is to come and so forth. It's not commercials for products. But there is a way to opt out. Click here --> Netflix.com/DoNotTest and go through the settings to not get this feature.