I've mentioned Carol Tice's Make a Living Writing – her newsletter is one I get in my inbox daily, and it's helpful because of a lot of useful advice.
In fact there are several email alerts and newsletters I get (and I do both my own and the Geek Scanner), and I find these useful for any number of reasons – good resources, useful advice, etc. But there's one important trait all newsletter have.
They nudge you.
That email is in your inbox, arriving regularly, reminding you. You have to do something with them – answer them, file them, something. You are regularly reminded of the knowledge within them.
Oh sure, you can ignore them or filter them. Of course they become reminders as you do so, little clouds of electrons that remind you that you're ignoring all that advice you wanted.
You can overdo this (trust me, I have before). But it's a nice way to remind yourself to read the advice you signed up for – and why you signed up for it.
Go on. Annoy yourself into productivity.