If you have a new wordpress blog (or any kind of website in fact), posting new content daily is a must. What makes wordpress unique is the fact that whenever you publish a new post, a ping is sent to the search engines and some blog aggregators service such as feedburner and technorati. A ping lets them know there are new contents and essentially invites them to come and pay your blog a visit, which is what you want.
For a new blog, these pings that are sent out are invavluable. Assuming that it’s a totally new blog and you don’t have other older or autority sites to link to you, posting new posts is the most direct way and the least that you can do to ensure yourself a little placement on the search engines.
Once you have more stable traffic, readership and backlinks, you can then settle for a choice of either to keep your posts updated daily or once in a while. However, for any starting traditional weblog with a shoe string budget, you don’t have much choice other than to do what you’re suppose to do on a blog or website – write good content daily