It's either. You can use TurboTax Online or install the TurboTax software on your computer. It's actually been available both ways for years.
To purchase the software to install on your computer (CD or download):
https://turbotax.intuit.com/personal-taxes/cd-download/
To use TurboTax Online:
https://turbotax.intuit.com/personal-taxes/online/
