Mommy, what's a blog?

According to a recent article, about 23 percent of children in nursery school -- kids age 3, 4 or 5 -- have gone online, according to the Education Department.  My children are part of the 23%.  I never let them go online unguided.  They are usually in my lap and we visit kids web sites or send an email to grandparents.   Tonight, I showed them how I can  "put their drawings into the computer" and add them to Mommy's blog.  Harry asked, "Mommy, what's a blog ..."  I told him it was a web site that similar to journal that he writes in paper but the blog is on the computer/Internet so other people can read it.  (He writes a journal in Kindergarten, so he made the connection.)  He then asked me, "Does that mean other people will see my drawing and tell us what they think about it?"   I said, yes, people do that, but not all the time.