"Blawg" is derived from "blog," which in turn is derived from "web log." A web log is essentially an online diary, which is more or less what this is. Only I don't write about emotional stuff, just pop-culture stuff.
The "blawg" spelling is how someone from Jersey might say "blog." And I came up with it fully expecting the domain name to be taken (I figured every combination of six letters or fewer had been registered by some speculator.), but it was available. So I took it.
For more about the cat what writes this blawg, click here.