Whatever product you decide you would like to promote, make sure you check that company's terms and guidelines. Although we are pretty much free to advertise as we wish in most cases, some places have tighter rules.
This means that before you accept a product, you need to read through the details that we normally quickly scroll through without reading. All businesses must fear spamming by their affiliates. Fines and penalties are tough for those that spam, or allow it to happen through their representatives.
Just make sure that you know the rules and abide by them, or you might end up dropped. Some places don't even allow the use of safelists, even if they are double opt-in. Others might want prove of opt-in from your subscribers if you have your own list. Whatever the case, just be sure to play by the rules so as not to damage your own reputation.