DidTheyReadIt.com is described as 'Free email tracking trial! Instantly track emails. Find out when, where & how long recipients read your sent emails. Receive email message read receipts'. There are six alternatives to DidTheyReadIt.com, not only websites but also apps for a variety of platforms, including Windows, Linux, Google Chrome and Microsoft Office Outlook. The best alternative is Bananatag, which is free. Other great sites and apps similar to DidTheyReadIt.com are Intelliverse Email Tracker (Free), GetNotify (Freemium), iTrackmail (Freemium) and ClickNotifi (Paid).
The Intelliverse Email Tracker application lets you know WHEN your email was opened, WHERE it was opened, and on WHAT device. With these insights, you can more strategically plan when to follow up on your email.
Email and document tracking service. Email notifications, and/or SMS/ICQ instant messages when email they've sent gets opened, and can even track reads of attached files such as PDF, MS Word and Excel documents.