How important is the frequency of updates on a blog?

Matt's answer:
Here’s a fun question from Land Lubber in Colorado. Land Lubber asks: “Some people are under the impression that blogs are good for SEO only if they’re updated frequently. How much does frequency play in to PageRank for blogs and other dynamic sites? Isn’t the content more important than the simple number of posts per day, or per week?” The answer is yes,content is much more important. So if you’re thinking about for people, then frequency might be a nice thing to have. If you show up on a blog everyday and its never been updated, and you’re a person, then maybe you don’t show up every single day, maybe you show up once a week. So people have noted that the more often you post, the more you have fresh content, to the degree where sometimes, some megablogs will have like a new post every few hours, just so that any time you show up during the day, you’ll have something new to read. That’s fantastic for users. Users like to see something different, not just the same static content whenever they show up. But whenever you’re thinking about search engines, it’s much, much, much more important to think about the quality of you’re content. For example on my blog I don’t post everyday. Sometimes I don’t post every week. But I try to make sure that each post has something useful about it, or some kernel that’s going to be helpful to people, that’s funny, that’s interesting. If you need to take three weeks to do some research, and then that research results in a really good blogpost, whether it be about the iPhone, or the Android market, or how well does gmail do web spam or…whatever it is… How much does Gmail detect spam compared to other webmail providers? Whatever it is, those original pieces of content often attract alot more attention than those sort of follow-on blogposts where you’re talking about, “Oh, I’m the one hundreth person who wrote about an iPhone that got leaked, and I don’t really have any new or interesting different insights.”…or something like that. It’s a lot more interesting to take a little bit more time. Think about sites like Techdirt. Mike Masnick doesn’t just follow the headlines and write about everything just to write about something. He’s told me that he waits until he has some insight, some unique angle, some of value to add, some perspective that people haven’t really noticed on a particular story. And I think if as long as you’re doing that on your blog, or on your website, it’s going to be a lot more useful, it’s going to attract a lot more links, and it’s going to do much better in search engines. So don’t just pay attention to, “I have to have a certain frequency of update per day”, unless you’re really trying to make a play to get a lot of users, and you’re really caring about how people are gonna be coming back to you’re site, as far as return visitors. If you’re thinking about search engines, what’s much more important is the quality of the content, rather than the frequency with which it’s posted.
by Matt Cutts - Google's Head of Search Quality Team