Peter Westwood

This plugin allows your users to configure a reminder to be sent to them if they haven’t posted in the last n days.
You configure the reminder on your Profile page (or the profile of another user if you have than capability)
It is in the Personal Options section and called Blogminder Threshold

PJW Blogminder

This plugin allows your users to configure a reminder to be sent to them if they haven't posted in the last n days.

Keith Ratner

Yourli.st is a smooth, registration-free online service for sending yourself reminder e-mails. The concept for this plugin came about as I was developing my cooking website, <a href="http://www.screamingsaucepan.com" rel="nofollow ugc">ScreamingSaucepan.com</a>. It occurred to me it might be nice to be able to remind myself about recipes in some way other than tagging them on del.icio.us, perhaps at a time when I might be wandering around the aisles of the grocery store. This plugin has only the most basic functionality, no administration panel, no options. It simply opens the yourli.st page and prepopulates the Event Title field with the title of the blog posting and inserts the permalink in the Event Summary. All you need to do is fill in your e-mail address, target date, and whatever other options you’d like to adjust.

yourli.st

This plugin opens the yourli.st page and prepopulates the Event Title field with the title of the blog posting and inserts the permalink in the Event  …

PJW Blogminder vs yourli.st