I would suggest that you think carefully of what you want to put in your signature and how to word it.

You will note, for example, that my signature does not mention my book or even the possibility of buying it through Amazon (or anywhere else). It talks only about me.

If someone is interested enough to see what I mean to click on my signature he will then be brought to the Amazon site where the book is being offered. Personally, I see a very big difference between that and if I had made a signature which reads, "Interested in new widgets? My employer makes the best ones" and then linked to your employer's products on Amazon or anywhere else.

Perhaps you might want a signature that reads, "I'm a great inventor" and then have it link to widgets that you invented. The signature would only tell us about you -- not your employer's products -- and be much more in line with what I have done.