We are not sure if they had these before but we just noticed it today.
Twitter rolled out the new design buttons for Tweet and Follow yesterday.
Here are some new ones…
They have updated the dashboard where you generate the code suited to your requirement. And they have two new buttons available here!
There is a hashtag button that can be used by services focused on events and topics. Clicking on this button opens up a tweet box with the hashtag prefilled.
The other button is mention which is also pretty useful. You can add it to your website to make it easy for your visitors to send you a quick message on Twitter.