Sometimes, when answering a question, I have taken advantage of the availability of online calculators. Theses calculators do specific and useful calculations like determine the grams of water in air based on relative humidity.
In many instances, these calculators are part of business websites as a customer service.
If I attach a link, then I'm attaching a link to a business which could be misconstrued as using the Stack Exchange to promote a business.
Is this an issue? Is there a Stack Exchange policy on this?