Twitter’s message window limitations to allow only 140 characters per update has forced twitter users to look for alternate means to cut down the message size. Hash tag is one such solution.
Hash tags are the short forms in twitter that refer to some phrase or event.
For example when somebody tweets as “Twitter was a Gem until they screwed it up #fixreplies”
here the has tag #fixreplies is referring to recently announced twitter policy update where one won’t be able to view replies made by twitter user whom they are not following.
So you see, use of such hashtags greatly reduces the message size.
There are many such hash tags in use on twitter and new ones been invented and put to use daily. So for some this can be very confusing and weird to make out the meaning of all those hash tags.
Tagdef is one such online tool that keeps track of all the hashtags in use and defines them with help of twitter users.
Also if you remember of introducing a hashtag to twitter language then go to tagdef, search and see if it is included there, if not then add your own and assign a definition to it.
Certianly this little tool can help a lot in increasing hastag awareness among twitter users.