I commend your desire to be polite!
However, since your question is specifically about “stackoverflow sites”, I recommend you do not respond to “thank you” comments or post your own “thank you”-type comments.
The “What should I do when someone answers my question?”
section of the site's Help Center says this: Please do not add a comment on your question or on an answer to say "Thank you".
Comments are meant for requesting clarification, leaving constructive criticism, or adding relevant but minor additional information – not for socializing.
If you want to say "thank you," vote on or accept that person's answer, or simply pay it forward by providing a great answer to someone else's question.
ell.stackexchange.com/users/54114/rob mayoff
All your examples are fine.
I would offer the following advice to make it sound more natural to a native, however, the most important of which can be summarised by saying keep it short .
Shorten
"You are welcome" to "
You're welcome" .
You don't necessarily need to say
I'm in the follow-up sentences, as this is obvious to the reader from context.
Saying something like "Happy to help" or "
Glad it helped" is fine.
In fact, if you use the word "I" or "me" too much, it can come across as being self-congratulatory/boastful/self-centered/self-important.
The simple acknowledgement of thanks is often sufficient ("You're welcome"), you don't necessarily also need to state your happiness for being helpful.
(Flagrantly stealing from Robusto's comment)
You can often shorten "you're welcome" or "no problem" to the acronyms YW or NP .
Use exclamation marks or smiley faces to appear more jovial, e.g. "Happy to help!" or
"You're welcome :)" .
Contribute is probably more appropriate if it was a group effort, e.g. a discussion, otherwise, help is probably more appropriate.
You can also use "to be of service"
(e.g. "Glad to be of service"), but "help" is again probably more informal/generally appropriate.
If you don't know whether the OP has found something helpful yet, you can use "I hope" to indicate that you would like your contribution to be helpful.
You could say something like
"I hope you find it useful/helpful" .
(Especially if you are Australian/speaking to an Aussie) You can use the phrase "
No worries" in a similar way to "No problem".
ell.stackexchange.com/users/51806/SteveES
None of the above.
Comments are not supposed to say thank you or anything in return.
Comments are not recommended for any of the following: Compliments which do not add new information ("+1, great answer!");
instead, up-vote it and pay it forward;
Source: https://stackoverflow.com/help/privileges/comment Edit
: Comments are not for extended discussion either.
ell.stackexchange.com/users/54127/leymannx
Your responses #1, #3, and #4 are entirely appropriate since you're answering directly to an individual.
#2 might be more for a general or bigger audience/community.
Depending on what the original question was
Glad I could help.
Good luck! may also be appropriate.
ell.stackexchange.com/users/26439/Peter
When people thank me I usually say: You're welcome, glad it helped.
By the way thanks are immaterial in the Stack Exchange sites, so you can vote on or accept my answer if you find it useful.
By saying so you also have the chance to get an upvote.
ell.stackexchange.com/users/55385/nawdeh naw
In order to be polite and answer in a social way I have had some hesitation to choose which phrase I should use.   You are welcome. I'm glad it helped.  You are welcome. I'm glad I could contribute.  You are welcome. I'm glad that I could help.  No problem. I'm happy that I could help.   If you have better phrases, please add, since it's fun to learn more.
How should I reply when I answer some question on Stack Exchange sites, people thank me and say it helped?
ell.stackexchange.com
<phrase-usage>
ell.stackexchange.com/questions/127213
ell.stackexchange.com/users/51666/Adam
"You're welcome, glad it helped" is one suggestion. However, people prefer votes on stack exchange. If you want to say "thank you," vote on or accept that person's answer, or simply pay it forward by providing a great answer to someone else's question. If you want to say "thank you," vote on or accept that person's answer.
If you want to say "thank you," vote on or accept that person's answer. When people thank me I usually say:   You're welcome, glad it helped. By saying so you also have the chance to get an upvote.