I was curious of course to know how my blog gained this ranking. Following various links took me to this explanation, which I'm copying here for anyone interested to read:
Our influence measuring methodology is based on the Input/Output model developed by the Nobel Prize winner Wassily Leontief.
The model takes into account all references and citations between the blogs. We developed three metrics for each blog: Influence Index, Popularity and Over-Influence.
The Onalytica Influence Index is the impact factor of a blog, or how much that blog matters.
Popularity represents how popular or well-known the blog is among other education blogs.
Over–Influence seeks to capture how influential a blog is compared to how popular it is.
There is a strong correlation between how popular or well-known a blog is and its influence. However some blogs carry more influence than their popularity leads us to believe; this is what we call over-influence.It seems that for me, this ranking was caused by the over-influence of the blog. I think I write for a fairly niche market (international school educators) so I would be surprised to find it was well known or popular. In any case this tweet made me happy. It is an honour to be on this list!