The LEVEL 3 PLAN is for business professionals and works very well for the communication needs of small/medium sized organizations (contacts, inquiries, pre-sales questions, customer support).
The LEVEL 4 PLAN is ideal for HR departments to provide employee onboarding, continuing professional development, and certification programs, and/or educational institutions in support of job (re)training, with its 1-to-many virtual classroom environment as an adjunct to online courses.