Why should freecycle be free? Let us count the ways...
Freecycle was freely given away hundreds of thousands of times by the people who created it and popularized it. When you give something away, you should not have the right to take it back.
Freecycle is a great new word that accurately describes a popular activity (to reuse/recycle by giving trash away to someone who actually wants it and can use it rather than putting it in a landfill).
Freecycle is either a compound word combining "free" and "cycle" or it is a portmanteau combining "free" and "recycle".
No other word accurately describes the act of freecycling and words by their very nature must be free for all to use.
Giving, is just giving and has no connotation of environmentalism or recycling, freecycling is a specialized form of giving.
Recycling is recycling -- reusing materials, freecycling is a variation on recycling.
Reusing is reusing -- and does not necessarily mean giving away for reuse.
Gifting is usually associated with purchasing and giving something valuable to someone special, it has no connotations regarding recycling or environmentalism or that you have trash you will dump if no one wants it.
Regiving is not a regular "official" word and also implies giving again -- when you have purchased something you could then freecycle it but regiving makes less sense.
Regifting is a popular well known activity -- after you've received a gift you don't need or don't like -- but this does not capture what freecycling is really about.
Freesharing, freeusing, etc are all new constructs that do not have the same ring or popularity as freecycling and also do not capture the nature and spirit of freecycling.
The New York Times, USA Today, Wall Street Journal, Associated Press, San Jose Mercury News, Grist, and many other news organizations have all used "freecycle" as a word and if they can, why not everyone else?
Goodwill Industries feels no need to corner the market on goodwill, so why should The Freecycle Network be the only group that can engage in freecycling?
The very nature of freecycling encourages the word itself be freecycled.
Freecycle is a simple concept that does not need an expensive bureaucracy to control it. By letting it be free, there can be many freecycling groups and services which can compete with each other. Competition makes each better (rather than having a central authority govern freecycling).
There should be as many freecyclers in the world as possible so it will be a better place. This is the whole point of the freecycling grassroots movement. Both freecycle recipients and givers benefit.
(A word to the wise: If you want to trademark something, don't invent a new word and expect to control it. Rather invent a new generic word and let it be free. Then pick a separate mark that is identifiable but not prone to becoming the word for a thing. This can be protected by being a trademark. For instance, drug companies ALWAYS have a generic name in addition to a brand name for their medications. Otherwise your "mark" may just go the way of yo-yo, escalator, etc.)