A lightbox subscribe form is a particular form of lightbox popup dedicated to collect email newsletter subscriptions.
The subscription offer appears after few seconds on a landing page or home page in the form of an overlay popup window as the main page is darkened and inactivated. This way, the visitor’s attention is focused on the offer though he may always close the lightbox with the closing cross.
Lightbox subscribe forms are intrusive but effective. Lightbox impact on list growth is indisputable, the effect on subscriptions is commonly estimated to be between 200 and 500%.
The choice of a lighbox implementation is a trade-off between instrusivity and effectiveness.
A lightbox subscribe form may be manually coded, but ESPs and some specialists offer turnkey solutions which only require "copy and paste".
An example of lightbox creation within an ESP service:
A turnkey solution: