blessay
n.— «I wrote a Frankenstein “blessay.” The reason there’s more “essay” than “blog” in that neologism is because there was more essay than blog in my contribution.» —“One Confused Blessay” by Scott Eric Kaufman Acephalous (California) July 28, 2005. (source: Double-Tongued Dictionary)
Blessay, to my knowledge, was coined by the writer, comedian, director and actor Stephen Fry on his blog http://stephenfry.com/blog/
It was a word for a piece of writing half way between a blog post and an essay.