In a new version of Tinder that is paid called Tinder Plus, there will be an undo button for those you accidentally swiped left for (apparently a very common problem). Still in development, Tinder Plus will have a number of premium features that will begin to bring in revenue for the dating company.
The undo button will be displayed prominently on the regular, free version as well to promote this feature.
In addition to the Tinder undo option you will have to pay for, Tinder Plus will also have a Passport option. This lets you search for matches outside of your geographic region. Being able to search for other Tinder users in different cities around the world will certainly appeal to those who travel frequently.