Peter,
Sorry for the delay in getting back to this. We're hoping to earlier in the week, but have done a bit of testing. Unfortunately, we can't recreate the issue. For an example of what we see (with SEF URLs disabled), we have a K2 blog view setup on our demo site:
demo.sourcecoast.com/index.php?option=co...gory&id=1&Itemid=173
That page has multiple articles in it. The URLs for the articles in the blog view on the Like button are the same as for the URLs when you click into the article. You can also see that the URLs are:
http://demo.sourcecoast.com/index.php?option=com_k2&view=item&id=2:social-media-marketing-tips&Itemid=172
When we enable Joomla's SEF URLs, we get a URL like:
http://demo.sourcecoast.com/k2-blog-view/item/1-how-to-integrate-facebook-with-your-joomla-website
That URL also is used for the Like button in blog views.
As you'll notice in the SEF URL above, the k2-blog-view (which is the menu item name) is displayed in the URL. On your site, the menu item isn't displayed. That's not normal Joomla behavior. Do you know why (or what) is stripping the menu item from the URL or anything else that may be configured to change the SEF URLs? If you're using a 3rd party SEF extension or plugin, that would be great to know as well.
Finally, if you don't know what's happening, then I guess now would be the time to send us admin credentials if you're ok with that. You can private message them to me by clicking the arrow under my name (<----) and hitting the mail icon.
Thanks,
Alex