Tags are basically labels associated with something for the purpose of identification. They are keywords. Its a way to remember things. Tags make it easier to find things when you want to search later. Tagging was popularized by websites associated with web2.0.
Definitions of Hashtag on the Web:
- In online computer systems terminology, a tag is a non-hierarchical keyword or term assigned to a piece of information (such as an internet bookmark, digital image, or computer file). This kind of metadata helps describe an item and allows it to be found again by browsing or searching. …(en.wikipedia.org/wiki/Hashtag_(metadata) )
- A tag embedded in a message posted on a microblogging service, consisting of a word within the message prefixed with a hash sign (en.wiktionary.org/wiki/hashtag)
Hashtags are a community-driven convention for adding additional context. It can occur anywhere. People use # just before a keyword . They are not official. There are no rules. You can follow some set etiquette that you learn.
Use of hashtags in tweets are very common. It helps to add context and metadata to the tweets. It helps to categorize. If you use hashtags in your tweets, someone who searches for that hashtag will find your tweets easily. It is used as a tool to track topics. Like Trending Topics in Twitter. An example could be #NewTwitter.
Some more examples:
Event : #epatcon #hcsm #fdasm
Phenomenon : #fail #spam
Products and Services : #iphone #ipad #youtube
Ritual : #followfriday(this is used to suggest interesting people for following—kind of who-to-follow-suggestions) done every friday worldwide.
You can also use hashtag for integration into other apps like #in for LinkedIn and #fb for facebook while routing your posts through other sites.
There are services now which help you with tools to look up a particular hashtag. They help you track the whole stream. They also point you to links, photos, videos etc…Some of them even define the hashtags for you so that you can use it to understand what the hashtags mean.
Read Social Media Tools and Market Research and see how useful #hashtags are for market research purposes as an example.
How do you Tag and #Hashtag ? What will you hashtag this post as ? #productivity ?