Traditionally, you publicised your blog by getting it linked to by other blogs (ideally ones with a lot of authority), by carefully choosing your keywords that you want user to organically search for and by doing the same and sending SEA traffic to it.
Keywords can be chosen based on referring keywords, then writing more articles around these articles. My rather eclectic list of keywords that users used to get this blog yesterday were:
“agile best practices”
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best agile practices
If you believe your colleagues and friends will be more likely to enjoy your blog, then there are actually a couple of relatively new ways to publicise them.
Firstly, as social network move full hog into lifestreaming — which Facebook has always done to some extent, and is doing more, but which nearly every social network is moving into, more and more of your friends and colleagues see posts in the your lifestream before their see your RSS feed, because most people are more frequent users of one or more social networks than they are of feed readers.
Secondly, LinkedIn and other networks are allowing you to recommend blog articles to your colleagues and friends. If they read this, they may also read the most popular articles on the blog, or jump through to articles that interest them.