Weblogs are an important part of the internet: They allow normal people to express their opinions and thoughts to their family, friends and the whole world by simply publishing some text on a server. This process is very easy and you don't need a grade in computer science to even host a blog on your own or a rented server.
One drawback of blog software is mostly their user interface: Since it is browser based, it requires you to be either online all the time while writing your blog post, or write it in a normal text editor and copy&paste it when going online. Using a text editor you cannot apply font styles to your text.. An offline tool to write blog entries would be really nice in this case.
Considering the idea of an offline tool for writing blog entries leads to the availability of access to your blog from outside the normal web interface - e.g via web services. Most blog hosters and blogging software packages have support for such a web services API, mostly via XML-RPC.
Unfortunately, there are many different of these application programming interfaces in the wild. Some of them support only posting of blog entries, other ones also allow reading. Some blog softwares support images and tags in their posts, others not. The variety is large, and so you could end up writing custom code for every blog server you want to access because of the differences in their API.
This is the point at which Services_Blogging comes into play: It provides a unified API to post and read blog entries, independent of the API supported by the server software hosting the blog. It uses a driver-based approach to communicate with different APIs out there. If a new blogging API is invented, someone just needs to write a driver for the Services_Blogging package, and everyone can access also this blogs.
As of April 2007, the package has the following drivers: