My 15 year old was homeschooled. We consider peer interaction important, so we "orchestrate" his peer exposure.
We invite teenagers over to our home a couple of times a month to "hang out" and play pool or board games.
We know the kids (mostly other homeschooled kids) and lots of times the parents stick around as well.
It's amazing to watch a group of teenagers having a good time, and not being bothered by the fact that their parents are in the living room.
In fact, we've often commented about the socialization issue, in that through the evening the kids will drift in and out of the "adult gathering", sitting for awhile to talk, and then go back to join the teenagers.
Major bump for homeschool, nothing we did, just the result of not being peer dependent, and being able to "socialize" with people of all ages.
Also most of the high school home schoolers we know use our dual enrollment program at the local college. Pass the College Placement Test and you can take college classes for free that count as High School and College credits.