My first exposure to homeschoolers was as a 3rd grade student.  My mom would travel to a local private school and purchase some textbooks and each week we would go meet with other homeschoolers at a church.  I took a US history course taught by my friend's father and my mom would teach the younger kids. This was a traditional co-op.  30 years ago, they were the most widely used sources of community for homeschoolers.  Well, that's not the case anymore. 

The co-op still exists, but it thrives or struggles alongside tutorials, online courses, duel enrollment, and everything in between.  Let's start by defining some terms, shall we? 

• CO-OP : A co-op, a cooperative, is a group that pools their resources for a common purpose.  Oftentimes these are volunteer based.  As in, I volunteer to teach the kids math and in exchange, you will volunteer to teach them english.  Co-ops are great because they allow parents to use their talents, but they are limited because not every parent wants to teach. 
• TUTORIAL : Similar to a co-op is the tutorial.  A tutorial is a weekly or biweekly group of people who come together for classes similar to a co-op, except instead of trading labor, they trade money.  As in, I teach the math class for a tuition and you teach the literature class for a tuition.  The 'teachers' are paid for their effort. This is great because if a parent doesn't want to teach; they don't have to.  A parent who chooses to teach can use their income to go towards his child's tuition to other classes. 
• COURSE : A course can be similar to a tutorial in that it may meet as little as once a week to as much as daily. Courses often take more responsibilities than tutorials by adding assessment and accountability. While full enrollment in courses start to bring the student out of a homeschool and into a private school, many homeschool students supplement their coursework with an occasional full course. 
• DUAL ENROLLMENT : Dual enrollment is when a high school student takes a college course.  Whether he takes it online or at the local community college, the class is counted as both a high school credit and a college credit, hence dual enrollment.  Sometimes, scholarships are available for high school students.
• TUTORING : The one thing that hasn't changed in 30 years, is tutoring. Hiring a tutor is pretty much the same now as it was in 1990. However, the internet has changed the medium of tutoring.  Finding an online tutor can often be more cost and time effective for both parents and students.