If you want to use symbols on Twitter or you want to use special characters, then her is a free web service, Twitter Symbol. Using this free web app, you get to add some amazing symbols like heart symbols, music symbols and other beautiful characters as your Tweets.
What makes this web app more special is the fact that it treats each symbol or special character as one character which lets you utilize your limitation of using 140 characters in each tweet.
And using Twitter Symbol is so very easy. All you need to do is log in to this web service, click on the button on top right corner which would connect you to Twitter. Now, you can use the provided symbol and tweet from there.
This free web service offers you with so many symbols like arrows, heart, zodiac signs, mathematical symbols, and loads of other symbols which can be used in your tweets.