I think what you’re really asking is can something exist without being perceived. Of course, in this instance, you’re forgetting that the person writing the blog — the blogger — will perceive the blog, so of course it exists.
This raises another question, though. If this fictional blogger — let’s call him Mankor the Metaphysical — is in a forest that is outside of a net connection, so Mankor has no way of publishing the blog entries to the Internet, does it exist?
I suppose if Mankor just blogs for himself, then perhaps we can answer yes to this question, because for our sad hypothetical Mankor, the act of blogging is not so much about having an audience read it, as it is of actually writing something.
On the other hand, some may argue that blogging is in essence a kind of performance — more than any kind of writing is, really — in which case, we’d have to say “no” the blog does not exist in the wilderness. It requires an audience.
On another prehensile appendage (remember, I’m an uber-chimp, so feet count) Mankor the Metaphysical may be barking mad, and believe that he has an audience, even if he doesn’t, in which case, he could well be performing his little heart out for his imaginary viewers.
On a final foot, let’s say that I have dispatched a troop of Gorilloids (armed with broadswords and wearing Fezzes) to dispatch this pesky Mankor, so he won’t be doing anything. Let alone blogging. And yes, if a blogger is hacked to pieces in a forest by a cadre of blade-wielding super-apes, there will be a sound.
It will be screaming. (And a fair amount of oo-ooo-ing from the Gorilloids.)