I’d like to display a checkbox with the option to subscribe to the site by email
I have seen a wordpress blog with the following label next to the said checkbox
Subscribe by email to this site
The problem is that i cannot see to find the plugin that displays it: i’ve tried Subscribe2 and Post Notification and Gurken for comment subscriptions.
Would you perhaps know what plugin i need to install?
There are often issues with setting up email subscriptions. Hosting providers are very tired of spam and often put harsh restrictions on email rate and volume, especially for cheaper hosting plans.
In practice such feature is often implemented with help of external service. FeedBurner is popular for this, because a lot of people use it for feeds anyway and it provides decent email subscription option.
See FeedBurner Email Overview and FAQ
You could take a look at WP Responder:
http://www.wpresponder.com
It supports providing email subscription to all blog posts as well as particular blog categories.
I’ve used Notifly with some success
Rarst makes a good point about using an external service to avoid issues with hosting provider restrictions.
However, if you have a less restrictive host (and you can check with tech support to see what the limits are for your account), the Subscribe2 plugin should do what you’re asking.