In filling out forms, I'm starting to see a lot of this:
Is it generally acceptable to join the words like that? Or should we be sticking to:
First Name: xx
Last Name: yy
It should be two words: "First Name"
There does appear to be an upward trend of lumping the words together, but it's still pretty small - and incorrect. I suspect some factors in that trend include:
I think the reason why it is written a lot like "firstname" is because in other languages first name is often one word (ex. dutch, french, german, Danish, Fins, Greek, ...). A lot of websites and forms are translated from other languages into English to go international. Everyone can read English. :)
I think we are seeing the language evolving. The technology behind the webpage almost always uses firstname and lastname in the respective variable names. Many programmers (including those who are raised and schooled in the US) do not have strong English skills, and they are heavily exposed to the single word variation.
I'd argue it isn't wrong, it's just a new variation that may someday become acceptable.