I sold a lot last year and have a filled in scannable 1099-S form. Will the online version read that document and allow it to be included as income?

TurboTax Online cannot scan documents. You need to manually enter it.

In TurboTax Online, you can enter the sale of land by following these steps:

1. Open your tax return
2. Click on Federal in the left-hand column, then on Wages & Income
3. Navigate to the list of income categories
4. Locate the section Investments and Savings and click on Add/Edit
5. Continue until you arrive at the page OK, let's start with one investment type. Select Other and click Continue
6. Follow the TurboTax interview to enter your information. 
7. If you incurred sale expenses, you can subtract them from the proceeds.