The caged bird singswith a joyous songof the captive life that kept it safe all along.This answer exemplifies the two birds: free and caged. Free in such a way that it is able to sing a song of its choice, and caged, because even if it is in captive it has something to be thankful for, its safety.
Many workers receive lots of emails everyday. If your email has an attractive, eye-catching subject line, it is less likely to go unnoticed. This is particularly important if you are engaging in e-mail marketing.
If your message contains sensitive or urgent information, a subject line can help you call this to attention. This means that your email will be opened immediately.
