While expressing gratitude in spoken Mandarin, I believe people use 谢谢 and 感谢.
感谢 imply a higher level of gratitude? Is there a difference in usage (stemming from culture, origin, etc.), or can they be used interchangeably?
I have also seen 多谢 and 跪谢 used in the signature of emails. Do these words implicitly convey different "levels" of gratitude?
I am a little confused with the difference in usages of these 4 forms of thanks. Any explanations or suggestions?