Well I have to say that after a little experimentation
What I can't fathom though is how it seems to generate a significant amount of visitors more than say more conventional conventional 'blog awarenness' routes. One of the commitments you have to make when joining the BE community though is spending time (approximatley 20 seconds)browsing blogs that might not have any interest for you. The benefit in browsing is that you get BE credits that you can use to buy banner impressions (it took me ages to fathom that you need a Flickr or Photo Bucket account to hold your banner -doh!) to promote your blog.
There is a community aspect to BE although it seems quite clunky compared to say Blogcatalog or My Bloglog. That said there are some interesting 'games' all with the purpose of collecting or winning BE credits.
I'd be interested to hear any views about Blog Explosion. Am I being gullible? Is there a catch that I'm missing?