I Agree with Carlo(he has more Google experience about this then I have). As an example, I have my own private swedish blogg about entrepenoruship and I see an instance surge in trafic when posting new content to the blog. Many of my visitors are using some kind of RSS-reader and subsribes to my blogg.
Now this content is my own but a lot of internet uses want help in categorising information and content and then pushed to them. Build services that supports this and you will have visitors to your website contiously.
Good content that are user friendly will drive traffic!
Also write good and intressting subject lines. An intressting headlines get a lot of attention!