Very important in the future please do not post the content of internal log files without changing details like email addresses to something anonymous. You've just exposed hundreds of email addresses of your company to spam bots crawling the web.
A combination of RegEx and the Group-Object cmdlet usually works great for me if I need to extract and count the value of properties. I've created a sample script for you which works on the log file you've provided.
Have you tried anything? If you simply want occurrences of the email address, you should look at a REGEX pattern for email addresses. If you want the date as well, you can find regex pattern for the date format and use grouping and match both with a single REGEX pattern.