Consider this before you join a for-profit wiki:

• The owner(s)/starters likely wish to make money from the site
• There will be paid members of staff - often they will not be the great help volunteers want them to be - they are so closely aligned to their contractual expectations that being of wider help doesn't cross their minds
• Paid wikians often feel they have a hard time of things and cannot see volunteer issues - it's a job, right? On the plus side, they really develop their ability with platitudes and reminders of what it is to be "open".
• Volunteer ideas, efforts and work are freely given - if paid workers take them up, you made a free choice
• If any of this is antithetical to your beliefs, just don't go near it.