How it works
The Mail2Cloud extension inserts an aqua-blue button bearing the service's logo to the immediate right of the "Send" button on Gmail's email composition toolbar. To set an email to be tracked, you write your email first and then click the button. A panel opens that lists functions that the Mail2Cloud service can apply to the email -- for example, to have the email tracked, you highlight Total Track, choose a time limit for how many days any files you attach can be downloaded, and then click the "Send" button.
The Mail2Cloud servers will then send you an email when the recipient opens your tracked email, when any link inside the email has been clicked (and it will give you the URL of the link) and when any attached file is downloaded. However, Mail2Cloud sends an email for only the first time that any one of these actions is done by the recipient.
On the Mail2Cloud site, you can access a list of all the times that your tracked email was opened, what city the recipient was in when they did so, what kind of device they used to access your email, what links in the email they clicked, and what attachments they downloaded.
Like Bananatag, Mail2Cloud also works with Outlook.
Free and paid plans
Mail2Cloud offers a 14-day free trial that lets you use all of its features. After the free trial period has expired, Mail2Cloud is available for $8/month for individuals. A business plan offers the same features at $5/user/ month for 3 to 99 users, and there is an Enterprise plan available for organizations with more than 100 users.
If you're sending a confidential business file and need to track and control its distribution, this is one option to consider. Only one other service I tested for this roundup, Yesware, tracks the status of attached files. Unfortunately, Mail2Cloud lacks a free option.
MailTrack lets you track an unlimited number of emails for free -- but there's an odd catch: Under a free account, tracking cannot be turned off.
How it works
With a free account, all emails you send are tracked; there's nothing else you need to do other than write and send your email as you normally would.
When the recipient opens your tracked email, a notification card pops up from the lower-right corner of your desktop, and will also appear among the cards listed in the Chrome Notifications panel. MailTrack will also notify you by email, if you set it to do this.
Sign up for CIO Asia eNewsletters.