2011-02-09: Migration now does tag checks. During migration, tags will be checked (and replaced if found) for tag synonyms on the destination site. Tags that do not exist on the destination site will be stripped from the question. If the previous steps leave a question with no remaining tags, it will be closed as off-topic on the original site and not migrated.
Most questions we receive are only tagged with latex, and we don't have that tag. Does that mean that migrated questions form SO or SU will now never arrive here?