As I recall, google is required to keep certain records of emails for years (someone please correct me if I'm wrong here, this came up in conversation with some people working on gmail so I may mis-remember). So even if you delete your email, it might be sitting in a tape archive somewhere until google can (legally) get rid of it.
That means you're under active investigation and there's already a subpoena or warrant in place.
If you don't want somebody reading your steamy emails or social media postings in the future, you have options... don't create them, delete, or store on physical media in your home.
This sounds awfully close to "don't worry if you have nothing to hide". How about this; I'll create whatever steamy emails I feel like, and I'll use services that preserve my privacy while I do it.
