We have created a WordPress addon that allow displaying a pop-up registration forms and automatically register new leads into Interspire Email Marketer. Addon is fully compatible with WordPress 3.5 or newer versions.
In addition to standad pop-up registration forms, you can hide your premium content behind an optin in order to increase registration leads. Besides the locking functionality, Optin Lock allows you to create in-content optin forms and lightbox popups, and add them anywhere on your website. It’s a must-have plugin for anyone building a mailing list.