I have been on Freecycle for a long time and whenever I see people offering pets I email them and direct them to their local rescue sites and sites like this that are dedicated to the rescue of the kind of animal they are trying to rehome. Normally I get a positive response and have seen lots of animals find good new forever homes. Occasionally I get an abusive email back, but it's very rare. The main problem with animals offered for rehoming this way is finding out that the animals either have really bad behavioural issues or an illness that is very expensive to treat and the owners just can't afford to pay for it, but are too ashamed of themselves for letting them get so sick, so they don't want to go to the shelters for fear of being prosecuted for animal cruelty. They hope they can pass the animals off to someone else privately. For these reasons alone I advise people to be very cautious of taking an animal on from this kind of source. Insist on getting vet checks before agreeing to take them on for fear of any surprises you might get. That doesn't mean you should never take on a pet offered on freecycle or gumtree, it just means you need to be sure exactly what you are taking on before you take the animal home.