It has always been "acceptable practice" to ask permission to link to other websites. Back in the olden days, when only geeks used the internet, that's how we did it. It was a way of tracking where your information was on the web. It was also usually a reciprocal thing--you link me, I'll link you.
While I still think it is good manners to do so, I can't imagine getting upset at having a blog linked on another blog.