As far as I know, they are a legitimate business, with a real web site. They are probably calling to get you to sign up and advertise on their web site for bridal vendor services.
I am in the wedding industry and they received my information from a conference I attended. Wanted to get feedback regarding the conference and wanted to see if I wanted to advertise on their website.
I am a wedding photographer. Wedding Wire is a place where a lot of wedding minded people go looking for service providers. Wedding Wire provides an online directory and of course there are various levels you can be listed. Obviously the listings where you are seen cost money. They offer a free account, but it's essentially just a way to get your info so they can call and bother you to sign up for services which will allegedly get you better exposure. It's legit, but still spam.