There are two general kinds of e-mail lists. Announcement lists are kind of like mass mailing, where a small group of people creates content and sends it to a larger group. Discussion lists are similar to a conversation, where everyone can send e-mail to the list. Blogs are more like the pamphleteers of the 1770's, or today's community newspapers: a small groups of people create content, but they hand it out at the street corner, or post it, to try to reach a potentially wide audience.
Let's start with how blogs are different from discussion lists, because that's probably the clearer distinction. The main difference there is that the blog's conversation is more one-sided. The person or people controlling the blog speak with a louder voice, because they get to decide what the article is going to be. Everyone else can post comments, or they can write their own blog entries, but the focus is on the blog article itself. It's closer to a newspaper and letters to the editor. In fact, similar to a newspaper, the blog's author can selectively delete comments. Since it's a one-sided conversation, the blog is more useful for situations where you want the organization to speak with a unified voice, like when talking to the public. The discussion list is more for socializing, strategizing and building consensus.
So, how are blogs different from announcement lists? The difference here tends to be about whether the focus is inside the organization or outside. Announcement lists tend to go to an organization's membership, or at least its power base, for a couple of reasons. The first is that it takes several steps to sign up for an e-mail list, so people don't tend to do it unless they're already interested in the organization. Secondly, when you sign up for an e-mail list, you have to trust someone else with your e-mail address and hope they don't spam you. In contrast, blogs are web pages. The search engines index them, and people all over the Internet can browse them and link to them. For instance, here is what you get if you run a Google search for the Dark Star Gazette. That difference makes blogs a useful tool for recruiting. The announcement list is how you get critical announcements to your membership: write your (politician of choice) about (this impending legislation). The blog is for distributing news that's not as time-critical, with occasional time-critical stuff thrown in in the hope that you'll reach people outside your normal power base. With the blog, you want to develop a regular readership that checks in periodically, while at the same time becoming a useful enough source of longer-term information that the search engines will index it.
So, to summarize:
- In discussion lists, members talk to each other. They're most useful for socializing, strategizing, and developing consensus.
- In announcement lists, a small group talks to the members. They're most useful for mobilizing the membership to action, and for announcements that should stay within the organization.
- In blogs, a small group talks to the public at large. They're best suited for general news, recruiting, developing a public image, and providing information and analysis as a public service.