Its futile. I should have put that on my 'fix Google' post. It doesn't save the words, don't be fooled to think you taught it anything. It doesn't recognize blog for goodness sakes.
I just spell checked another post, and you're right, the Blogger spell checker doesn't learn a thing. It suggests 'bloc' for 'blog.'
As one 'bloccer' to another, you'd think Google would sweat a few details like this, but perhaps they feel they don't need to.
Commenting by HaloScan
