BeWelcome vs CouchSurfing
CouchSurfing (CS) and BeWelcome (BW) are both hospitality networks. You can sign up and you can ask people if you can stay at their place and people might ask you if they can stay at your place.
CS: CouchSurfing International, Inc. was started in 2003, mainly by one person, out of a personal need. It was set up as a non profit organization in the US state of New Hampshire. In 2011 the non profit assets were sold to a C corporation set up by members of the board of directors for $600k and the B corporation certification was bought from the B Labs company. Consequently venture capital was raised.
BW: BeWelcome was started in 2007 by former volunteers of Hospitality Club (yes, another network, which is run as a sole proprietorship). It's set up as a non profit organization in France, named BeVolunteer.
 Decision making
BW: In BeWelcome.org, the Board of Directors are chosen yearly by members of BeVolunteer. There are strong tendencies against power concentration. Members of BeWelcome (who are not necessarily official members of BeVolunteer) can actively participate in all website-related issues through an open forum and a wiki.
 Code Source
CS: The Couchsurfing source code is kept private, even if most has been programmed by volunteers. All programming volunteers need to sign a Non-Disclosure Agreement and the code cannot be used outside of CS without consent of the owners.
BW: The BeWelcome source code is open-source and therefore not kept private. Programmers grant BW an non-exclusive right to use their work. This means programmers are free to submit the code elsewhere as well.
CS: As of January 2012, there are more than 3,6 million registered accounts in Couchsurfing. The member base is largely North-American and European.
BW: As of June 2014, there are more than 60,000 members registered accounts BeWelcome. http://www.bewelcome.org/statsin The member base is largely European.