Have a look at Why PR students love blogs at Josh Hallett’s hyku blog. My thought would be that all students should love blogs – but only very few do (and I’m reluctant to make it a compulsory assignment as that seems to defeat the voluntary, grassroots quality of a genuine blog.)
Note in particular this from Stuart Bruce’s comment on the above discussion. (Stuart takes some of my students on short-term placements, and he has at least one working on a client blog at present.) Here’s what he expects from students seeking work placements:
If a student hasn’t "given something back" then we won’t consider them. The pressure groups and politics might be contreversial with some but I’m still far more impressed by a student who has volunteered for something I disagree with than one who can’t be bothered to "give something back".
In short, he’s looking for passion and commitment. And a blog is a good way to demonstrate this.