You know, if you do not have a huge following on your fan page, making a few quality posts biweekly to monthly is often the best way to go without stretching yourself too thin for only a handful of people. More does not always equal better, except in perhaps Twitter's and Tumblr's case where people can easily share tweets and other content without going out of their way, then you want your posts to be short and sweet, but tempting to click. If something appeals to ten targeted people, chances are it can appeal to hundreds, even thousands if executed properly. You can also promote products at a good frequency, or maybe even post your latest article or blog post and feed it directly onto your page for quick views.