For those using
Virtuemart,
CSVimproved and
this hack... it is possible to use
CSVimproved to upload meta-keys in bulk with a CSV file.
I am by no means a
Joomla or
Virtuemart expert.
I just thought I would try this and it worked for me. If it doesn't work for you, I probably can not help you (sorry).
Here is how I did it:
1. I added a column to my
CSVimproved CSV file called "product_metakey" (see attached screenshot).

2. I added a "Field Name" to my
CSVimproved template called "default" (you can find it in the drop down box). This was on my
CSVimproved page called "Template fields::CSVI Product Import" (screenshot attached).

3. I added a column header in this same template called "product_metakey" (note that it matches the column in my CSV file).(same screenshot as #2)
4. I made sure the check box for this hack called "Turn On Manual Edit of Meta Title/Description/Keywords" on the Metadata tab for the products in
Virtuemart was checked.
5. Uploaded the
CSVimproved CSV file, checked my product in
Virtuemart, clicked the tab for "Metadata" and my uploaded keywords appeared.
It was used here on a few items:
http://www.maximummidrange.com/Regards