Here is one of the many reasons why it’s a good idea to have a posting at least every three days. I use my yahoo as a reader. It only shows posts from three days ago, and I have to confess that I don’t look at it every day. So if luck has it that I remember to check my yahoo on days that someone hasn’t posted for 3 days or more, all I see is the name of the blog. On most days, that doesn’t entice me enough to click and see what they’ve been up to lately.
How this works vis-a-vis email feeds like Feedblitz is a different story. I certainly don’t like getting a generic “2 new posts” in my in box every day. But once a week, I can handle that, and services like Feedblitz can do that.
So ideally, the regularity of the blog should reflect your readers’ preferences.
For example, I know that my readership drops dramatically on Saturdays and spikes on Mondays - so I always want to have fresh content for them by Monday morning.