You know if I get a marketing email entitled Proof It! How To Be a Better Proofreader, you’d better believe I’m proofreading it.
Oh, yes, there’s the typo. No, wait, it has two:
Also, bullet point items should consistently end with punctuation or not. Generally, you don’t want to mix and match–even if the outlier is an exclamation point!
On the other hand, it did make me read the email more closely than I would have otherwise. My engagement is up, but my conversion from prospect to sale remains false.