The company MailTrack has become very successful thanks to its ‘double check’ for Gmail, which lets users know if an email they’ve sent was received and read by the recipient. It’s a similar system to those used for instant messaging.

Until now this type of ‘double check’ system to notify email senders when their mail has been opened only existed for business customers. MailTrack has recently brought this service to individuals as well, helping to reinvent email.

‘Double check’ technology consists of including a pixel tag with a message. This is received by the server and enables notifying the sender that the message has been opened. The tool is now available for Google Chrome and Gmail, and versions for other platforms are being developed. In fact, two months from now an application for smartphones will be released.

The system also lets you know how many times the message has been viewed and at what time. With Yahoo and Hotmail (but not Gmail) you can also see where it was opened. The company’s product is free of charge and will remain so according to MailTrack. However, other value added functions that MailTrack is now working on will be for paid subscribers, such as services for professionals.

MailTrack is also working on a tool that will let people program their email and determine when messages will be sent. This function will be very useful for people working across different time zones.