You can make money on Bitcointalk by the signature campaign, or by selling your goods and services and skills, or also by participating in the give aways.
Yes this are the basis ways to earn money on this forum and the best thing is all those ways are genuine and trustworthy ways of earning bitcoin, the chances of getting cheated are very rare.
No one will cheat you on this forum if you are yourself not willing to be cheated, because mostly people here are not scammers and if there are scammers you should know them by there actions or by there talks that will reveal them in public.
That's true and if you find some phishy or suspicious then it would be better not to get involved into it and stay away from it as no one likes to get scammed or cheated.
