Professional wedding blogs are alive

Hold on your expression, if a seller is paying for a blog de mariage web log entry, surely they would need their name/business/website mentioned many times in addition to a thorough breakdown of who they are, what they offer etc?

Yes of course they will want all that, and so a vendor can pay for that type of blog entry, which is called a "sponsored listing". In sponsored listings the vendor can go to town with a completely detailed explanation of who they are and what they offer, and generally the wedding blogger will go for the "interview" with these types of "sponsored listings". But more often and not, wedding vendors will opt for the more regular blog post.