Using hashtags on twitter has become somewhat pointless, since when you search for tweets you get all tweets, not just those with hashtags. However, if you want the word to be a click-through "search", hashtags are very convenient. This is useful when you're tweeting about current events, when you want to be noticed in a stream of tweets about current events, or when you're trying to start a trend. A little entertainment on this topic:
Hashtag started with Twitter, later it extended to other social networking sites, a hashtag is simply a way for people to search for tweets that have a common topic.
"#" looks very "computerish" I'd say. Hate it when text looks too much like a prison cell window. And I hate its intrusion into FB
Hashtags are just a way of grouping conversations by topic in a sense. Here's a useful article on the subject of hashtags: http://socialmediatoday.com/warren-knight/2354491/how-use-hashtags-increase-your-social-media-presence Hope it helps.
A hashtag is a word or a phrase (without spaces) preceded by the # symbol that helps people find and join conversations about a particular topic.