&gt; Legally speaking, a lack of case law means the jury’s out. But for brands striving to connect with their constituency, it’s clear that more explicit permission is needed for brand-based tags (e.g. #calvinklein), or more complicated tags (e.g. #caughtondropcam) need to be used so that the claim of implied consent is more defensible.<p>Specific tags only solve half the problem.  Someone could copy the tag from someone else without being aware of the campaign going on.