It seems that there are a lot of hashtags appearing on ads in traditional media, and I wonder at their value.

Some conversations are simply not worth having, and so inviting one by using a twitter hashtag is absorbing some of your hard earned brand credibility, for no return.

Building a brand is still a difficult, long term, brick by brick effort, and wasting some of that effort by following the lastest fad pushed by a 20 year old with a beanie seems futile. 

Even in the “old days” when you could block the few broadcast channels with advertising, it was still consumer by consumer, it is just that we could not see the process, as advertising, particularly mass adverting is a one way, non accountable activity.  However, consumer by consumer, user by user, you still had to touch them in some way to motivate a modification to their behavior over time. If successful, your consumer built a relationship with your brand, if not, well, the failure on an individual consumer level was largely invisible. Apart from a very few individual cases, such as market research, a complaint, return, or conversation at point of purchase, the possibility of individual contact was very limited.

No longer. Now, we have the potential to see the whole process unfold from initial display of interest, to purchase, and post purchase behavior, if we are smart enough, and game enough, to put in the tracking mechanisms. These mechanisms make marketing investments accountable! Imagine, the end of the waffle!

Just putting a hashtag on the end of an ad, and hoping for the beginning of a worthwhile relationship is likely to be completely unsuccessful, and probably counter-productive, consumers are way too smart, and advertising savvy to be herded like the sheep of old.