This is what I'm doing right now:
I point from my articles to a testimonial landing page where I say something like "This product is great, it changed my life, I highly recommend it". Then from there I link to the vendor's sales page.
This is what I'm going to do now:
I will now point from my articles to a squeeze page and start collecting their emails. I know the basic stuff about email marketing (give lots of value and build relationships).
Now my question is:
Should I expect a increase in sales? If so, how much? Double? Triple?