This is a much muted point vivandorron.
Some will politely put TIA if they know that they will be unable to respond to any answers (until perhaps later - or on another day). Like in the outside world, there are those that are not polite anyway, and do not either think it necessary or are expected to say those little words "thank you" and "please". Shame, cos it doesn't take long to say it, and it makes you feel better, and makes the recipent feel a warm glow that they have helped (not always lol!!), and the questioner has acknowledged receipt of the post.
Some will say it is only cyberworld (not real), but I don't agree to that sentiment, after all we are all real people - not an electronic machine or automatic system like Google and Wikipedia. Testament to that - what about all the chat and camaraderie that goes on between the ABers? If peeps come on here to pour their heart out, or share a problem, that is real enough if they are seeking a human response to their plight. Stars are awarded usually for good replies (even if the poster does not agree with your opinion on a matter). At least that means that the originator of the Q has seen the reply and taken the time to show their appreciation.
I like to thank peeps for a reply, and love to receive one in equal amounts. Have always been polite to everyone and anyone outside, and do not think it should stop when I switch my laptop on.