Do you want your emails to be better than text—or better text? Find out here how to send richly formatted messages with OS X Mail and pick fonts and font sizes, for example, change colors, add images inline, and more.
Do you get the Gmail error "too many simultaneous connections"? Find out here why this failure might occur (certain email programs, settings and third-party services can cause it)—and steps to take to fix it.
Not sure you signed out of iCloud Mail like you should after you checked your mail at a friend's computer—and their OS account to boot? Fear somebody might be reading your mail without your notice? Sign out of iCloud Mail wherever it may be open at icloud.com right from where you are now.
When Yahoo! Mail encounters a suspicious log-in attempt (from a new country, say, and computer), it can put up a second authentication hurdle after the password: two-step verification demands a code received via mobile phone or answering security questions.
Beat application/ms-tnef and winmail.dat. Here's how to configure Outlook to make sure it does not send mysterious and inexplicable winmail.dat attachments with your emails to unsuspectingly confused recipients.