Today I needed to move some contacts (about 100 or so) from my wife's phone into a new Google account I set up for her. Unfortunately the upload page on Google's site only allowed individual uploads and it would have taken hours to upload all contacts one by one.
If you are, like me, on OSX (or Linux) you can quite easily combine a folder full of .vcf contacts into one by using this command (navigate into the folder which holds the .vcf files first):
I'm sure you can do something similar on the Windows command line too. In fact I've Googled it for you. :-)