1. Output video to dropbox by using the share function or saving directly to a folder linked to dropbox. 2. Go to vimeo and import the video from dropbox because they have integration now directly which is a much faster upload than going directly from your connection.
It's one in between, and it would be better to go to Vimeo directly from SnagIT (including tagging, collections, folders and all the other cool stuff Vimeo helps to organize videos).