In most cases, it's beneficial to use both. Place an embedded signup form on your main landing pages (homepage, contact page, etc.) and use popup forms to attract attention at critical moments. For example, after a visitor has read a certain amount of an article.
Whichever signup form you choose, there are some psychological business email address list poland tactics you can use to get more people to convert.
Back in 1984, Robert Cialdini wrote a book called Influence: The Psychology of Persuasion . It was based on observations Cialdini made during training sessions at used car dealerships, fundraising organizations, and telemarketing firms. During those three years that he spent "undercover," he defined the six basic principles that make people say "yes":
Reciprocity – Give a little something to get something in return
Commitment and Consistency – Get people to commit to something and they will follow through on that first commitment
Social Proof – People are influenced by the actions and opinions of others
Authority – People tend to follow orders from authority figures
Taste – The more you like someone, the more you will be convinced by them
Scarcity – The less of something there is, the more people want it
More than three decades after the book was published, these principles are still fundamental to a successful marketing campaign. And can be used in a sign-up form to tremendous effect.