Global Networking Websites Research

I'm looking for someone to conduct online research and check my list of websites where people can add their professional profiles primarily for networking purposes. The focus should be on platforms with a global reach. From the list I have I need:

+ the exact url where I sign up on each site

You are free to add sites to the list if you can find some that I missed.

Ideal Skills and Experience:
- Strong research skills
- Familiarity with professional networking platforms
- Ability to compile data in a clear and concise manner
- Understanding of the needs of a globally oriented professional
- Previous experience in data gathering and analysis

Examples:
www.linkedIN.com -> https://www.linkedin.com/signup?trk=guest_homepage-basic_nav-header-join
www.about.me -> https://about.me/signup/start