I am just getting started on Twitter. Would you explain what are hash tags, how do they work and how are they used?
This is an interesting question because to me it highlights one of the great strengths and weaknesses of informal community-driven social networking: the need to have a way to group tweets associated with a specific topic and the inability of the tool (Twitter) to offer direct support of this requirement.
It is ironic that one of the main reasons that Twitter arose as a popular tool in the first place is because of people at conferences (notably SXSW) wanted a tool that would let them stay in touch and coordinate informal meetups and such.
With thousands of users, however, how do you isolate those ‘tweets’ that are associated with a given event? There’s no “keyword” capability, no way for people to register on a central server indicating that they’re attending the event.
Instead? Add a simple, short word or abbreviation and then use something like search.twitter.com to find ’em all.
That’s what hashtags are. At SXSW this year, for example, I expect we’ll see tweets with #sxsw (the inclusion of the “#” is what makes it a hashtag, of course). Search for people who are including that in their tweets and you’ll get a running stream of updates from the event.
The big challenge with hashtags is that there’s no agreement on what tag to use and in my experience, almost all events generate 2-3 tags or more. For example, when I was at the Consumer Electronics Show, people were using #CES, #CES09 and #CES2009, which makes it hard to keep up while mobile.
There are also some Web-based hashtag services that have popped up in the Twitter ecosystem, notably @hashtags, though I am not always sure what benefit they offer over a more informal usage of the tags.
Hope that helps you out!