IPF must been one of the oldest pen pal clubs still operating. Since 1967, IPF has provided more than 1.5 million people aged from 8-80+ with pen pals in 192 countries worldwide.

• Penpals: 300,000 +
• Activity: Not sure but they have been going for 40+ years.
• Hidden email address: Yes (you post an application so email is not required)
• Internal messaging: No
• Profile pictures: No, well you can send them in your letters.
• Block penpals from contacting you: Not really, once you share your address.
• Ability to hide/pause account: Yes

Pros: Has been around for a long time and has many members and schools also.

Cons: You can’t search for pen pals directly on the web site. You have to send away a letter (which does make sense since that it what pen paling is all about) with a payment (it isn’t free).

IPF: http://www.ipfusa.com/