Cited by Barbara Nixon, How NOT to Hashtag in Twitter, Public Relations Matters (December 2010)
Hashtags are useful to tie conversations together. But how often should we use them?
Hashtagging nearly every word in the tweet is highly annoying. Far and away, the majority of hashtagged words in such tweets have no relevance, are not terms that would be searched, and are not terms needed for categorization. It looks desperate and spammy. Two is fine. One is better. And it is possible to tweet with —gasp— no hashtags!
Mike Styles, How to Hashtag (Without Being #Annoying), Oracle Blog (September 2012)
What effect do they have? Almost none. Other than making stuff harder to read. Or - I suppose (as in the case of #tcot) - as a handy dandy flag that expresses in shorthand your point of view or the context of your tweet.
In 53% of the social properties we analyzed, posts with hashtags actually performed worse than posts without hashtags. In 21%, there was no significant difference between posts with and without hashtags. And 26% of social properties had better performance in posts with hashtags.
Tristan Handy, Hashtag Stuffing Doesn’t Work for B2B Twitter Accounts, Social Media B2B (July 2011)
Seriously: is there any point in corporate hashtagging? I’m going with “no.” #YMMV