Mailsum 1.2 for Mac was available to download from the developer's website when we last checked. We cannot confirm if there is a free download of this app available.
According to the results of the Google Safe Browsing check, the developer's site is safe. Despite this, we recommend checking the downloaded files with any free antivirus software. Mailsum for Mac lies within Communication Tools, more precisely E-mail. This software for Mac OS X was originally developed by Appmasters Ltd.
From the developer:
Mailsum gives you full insight in your email behavior. It scans your email traffic and behavior, which helps you understand how you are using it. You can perform data analysis with graphs and pie charts. You can discover your most active hours during the day, see personal trends, compare with past performance, and more.
You may want to check out more Mac applications, such as Address Book to HTML, MailBrowser or Encrypt Mail, which might be related to Mailsum.