The New York Times recently published an article on abandoned blogs called "Blogs Falling in an Empty Forest".  In a nutshell, it says that many bloggers don't stick with blogging.  The article says:

"According to a 2008 survey by Technorati, which runs a search engine
for blogs, only 7.4 million out of the 133 million blogs the company
tracks had been updated in the past 120 days. That translates to 95
percent of blogs being essentially abandoned, left to lie fallow on the
Web, where they become public remnants of a dream — or at least an
ambition — unfulfilled."

So overall, that's not such great news.  Most blogs get abandoned because the blogger tires of writing, he/she feels like they want to go back to living a life out of the public spotlight, or because the blogger gets frustrated that she's not getting enough traffic. 

But the golden nugget of good news it that if you DO stay with blogging, and pay regular attention to your blog, you're doing better than 95% of the blogs out there.  That's pretty astounding!  If you make a post more often than every 120 days – FOUR MONTHS – you will keep gaining traffic, grow your audience, and you'll be well on your way to becoming a successful blogger. 

In the meantime, you can increase your odds of getting heard by concentrating on your content, promoting your posts in appropriate ways, and participating in the public conversation by regularly commenting on other people's blogs. 

In the world of blogging, it's the classic tale of the tortoise and the hare.  Just keep going, slow and steady!