There is a big trend going on...hyphenating last names. Especially working with kids, you really never know what a kid's last name will be or his parents' last names. I admit....we are a hyphenated family.
Personally, I hyphenated my last name when I got married because I was exercising my feminist tendencies. The reason why women change their names (e.g. being owned by their husbands) doesn't jive with me. Additionally, I like my name and didn't want to give it up just because I was getting married. I also thinks it represents the union of families. So, all our kids have hyphenated names. And so do many of their friends.
However, I find it very interesting that people often choose to drop one of our names. And I really don't understand why (with the exception of the intimidating Polish spelling). If your last name was Johnson...and someone called you John...you would think that was wrong. But people do it to us all the time (including my father on a personalized holiday present once). If I wanted to be known as a different name I would do that but I don't...I want people to call me and my family by our real names. (I will note that when ordering food, etc. I will often use my husband's short and easy to pronounce name).
Another problem of this trend is...what will happen when my kids get married? And what if they marry another hyphenator? Will names just get longer (Madeline Smith-Johnson-Beahm-Dean)? Will they drop part of the name? Will they create a new last name? Who knows...we'll have to see. (At least my kids middle names are also family names, to keep them alive).