The "Download" page of Tableau Public has a lot of the answers you are looking for: Download Now | Tableau Public. You may also want to watch some of the training videos: Resources | Tableau Public. I do not believe there are a maximum number of records but there are limits on processing time for data so if your Viz takes an hour to load, it wont work. Check out the Gallery for examples of what you can do with Tableau Public: Gallery | Tableau Public The one big difference between Tableau Public and all other versions is that ALL data must be open to the public. If you put data on Tableau Public, everyone will have access to it.
Data Sources for Tableau Public:
- Google Sheets
- Microsoft Excel 2007 or later
- Microsoft Windows Azure Marketplace DataMarket
- Text files － comma separated value (.csv) files
- Statistical Files; SAS (*.sas7bdat), SPSS (*.sav), and R (*.rdata, *.rda)
- Web Data Connectors
Hope this helps!
Thanks for your information Panuco.