I have been a member since late 2008 and have not looked back since. My first surfing experience was in Singapore.
Overall for me Couchsurfing was relatively safe. I guess I was pretty fortunate.
The generally rules were to check out the following:
-references from other members who met or stayed with them
-whether he/she has pictures and friends
-Whether he/she has been vouched
-whether he/she is a verified member (name and location)
It can be really difficult to get a host in major cities like Paris and Rome especially during summer. I sent around 10-20 requests in each city sometimes even more. I spent a great deal of time going through profiles and references. It’s like a HR Exec looking at resumes to fill up vacancies. Sometimes I have to post a shout out in the last minute group requesting for host.
If someone was unable to host or someone who accepted my request when I have already accepted someone else, I would actually asked them if they would like to meet up with me for drinks and coffee. Some ended up showing me around and offer me to stay with them the next time I'm back in the city.
Some hosts are actually people whom I’ve met in my home city and have become really good friends. Some offered me to stay at their place when I told them my plan to go to Europe but the problem was most of them will only be in Europe at certain time. So my itinerary was scheduled around their availability. So you will see that I traveled in a zigzag manner.
As precaution, I gave my couchsurfing ID and password to my best friend so she can check on my whereabouts from time to time. I even created a facebook event page for a group of close friends to post the details of my hosts' addresses and contact numbers. I guess you have to be tactful and practice common sense.
Personally the only awkward moments was when I was in Dan Haag where I could not click with my host and in Prague where the place is full of cats’ fur. Other than that It was all good.
I attended some of the weekly meetings, from there I met people who eventually become my guide in some cities and travel buddies.
My hosts are the most awesome people. I extend my heartfelt gratitude to those who have welcomed me with open arms to their homes. I am forever indebted to them.
P/S: Lately there are creepy people with hidden agendas who have become members for the wrong reasons. Check out group posts for any indication.