I had similar sentiments about the vanity of blogging. But I also like to write, and found that posting something publicly forces me to take the task seriously and actually attempt to do a good job and/or follow through. I reconcile with my concerns of vanity by doing nothing to promote the blog. From what I can tell, I have yet to attract a single reader, other than spam bots. The added bonus to not having any readers, is that I don't have to worry if the topics I write about are interesting or original.

I consider the blog to be good writing practice, and if/when the time comes where a job I am pursuing requires some extensive writing experience, at the very least I will have a small body of work to show off.