Fonz....a blog (weblog) is just a little text site that people have started using to basically journal anything they like. It has alot of imbedded links and very easy to post to using either your own software or an online system like
blogger
Recently Google bought blogger.com and added a tool to their new toolbar to allow you to make these sites very easily.
An example is
the eros blog as you can see there is alot of text and links for Google and others to spider so they do very well in the rankings right now.
Google has hinted at adding a tab at the top of their search for blogs, just like the directory and news tabs.