Am I just pointing out the obvious when I suggest:
Don't put any incriminating information in your blog and then you don't have to worry about it.Yes, I have done (and perhaps will do) plenty of things in my life I would prefer not to share with my mother. And I can safely guess that my mother has things that she would rather not share with her mother. It's the way of the world.
People, this is the Internet. I design websites for a living and I know what do to promote a site, and the security measures to take to hide or protect files on a website. Neither practice is fool-proof. The Internet is public domain, the search engines are optimized every day by hundreds of people to find your site, and there are curious and unscrupulous people who do the same. My advice? Don't put anything on your website that you wouldn't want your mom to see.
Still have an urge to blog your life? Use a pseudonym, don't mention anything specific about your family, your town, your employer. Oh, and don't bad mouth people who might take it upon themselves to divulge your secret identity.
You have the right to remain silent
Remember anything you say can and will be used against you in a court of law... or by your mother.
(see also: How Not To Get Fired Because of Your Blog)