According to some research, looks like the subscribers of an e-mail list lose interest after a while (4 months).
Mailchimp posted an interesting article showing that adding social features to your e-mail can get you better clickthrough (CTR) rates over time.
Of course, I can’t complain either way, as I got great CTR rates on my last e-mail – even though it had been almost an year since the last. But since mine usually involve free updates, I imagine it’s bound to be different…
