Using a hashtag (the "#" symbol before a keyword) is like including a keyword in your tweet. It's an unofficial feature of Twitter but now widely accepted and supported, and is an easy way for people to search for and find a particular topic.
Here's how it works, using some of my own tweets from the last couple of days.
"Rock Of Ages" - Def Leopard Isolated Vocals. An unusual vocal in many ways. http://bit.ly/xnQ1b #recording #producers #vocals #bands
This is a simple tweet regarding a post from my Big Picture blog last week, complete with a shortened url link. At the end are the hashtags #recording, #producers, and #musicians. How did I select them? First of all both "recording" and "producers" appear in the tweet, but I researched them first to see what kind of searches there were by going to twitter.com/search. There I searched for "#recording" and determined that there was a sizable enough search so it was worth using, as was "musicians." I figured that bands would be most interested in this tweet and the blog post, so I did a search and found that "bands" was also sizable, so I used it as well.
Here's another way I could've used the hashtags in this tweet.
"Rock Of Ages" - #Def Leopard Isolated Vocals. An unusual #vocal in many ways. http://bit.ly/xnQ1b
In this case I embedded the hashtag directly into the tweet text. This works too but I find it too difficult to read and it can turn quickly into a negative for less sophisticated users, so leaving some room at the end for the tags seems to work a lot better.
Here's another example.
"The Magic High-Pass Filter. Some tips for using the mixer's secret weapon. http://bit.ly/dpL9bv #highpass #filter #mixing"
Same thing here. I did a quick search and discovered that #highpass had a lot more searches than #high-pass and #mixing more than #mixer (there was also some confusion with a food processor as well).
Since I've been using hashtags the traffic to my blog sites have gone up by about 50% and I've gained some more Twitter followers as well. Using hashtags is a great way to help people find you, but don't forget to include a link to take them to your blog or website as well, since that's the real goal.
Check out my Big Picture blog for discussion on common music, engineering and production tips and tricks.