The primary limitations of the Basic plan are:

1. No SSL in transit encryption available (no lock icon will appear in your web browser)
2. No access to our high volume email gateway for sending invitations -- you would need to use your own email account
3. You can upgrade to other subscriptions if you want, but the link to your survey will change (on the other plans, your link stays the same if you upgrade).
4. You cannot customize our templates (meaning you cannot change colors or replace our logo with yours).
5. No white lable domain option -- so you cannot replace our domain with a domain you own

All our plans have unlimited responses and there are no restrictions on which question types you have access to.