The Guardian has an article on Waterstone's sacked blogger, Joe Gordon. It includes the extracts from the blog that probably got him sacked. I suspect, like many employers, Waterstones will have a policy on directing bad language at fellow employees, which may be how he got into difficulty. This was on his blog, however, on his own and not company time.
If Mr Gordon's appeal goes to a sensitive regional manager he may be ok but if he does get reinstated there may be some tension in the Edinburgh store for a while.