Authors and readers can discuss about the writing of authors including ideas, experience design, hypothesis etc.,
Consider also participating to face to face meetings and research seminars.
(Since you are located near Paris, France and seems interested in PHP)
If you are near Paris and interested in information technology, INRIA, ENS Ulm, LIP6, Collège de France, CNRS, CEA LIST have many research seminars that you can attend freely, and ask questions about your ideas. Also AFIA. I gave there a talk yesterday related to http://refpersys.org/ at a seminar in honor of the late Jacques Pitrat.
On a more industrial mode near Paris, consider attending Systematic or CapDigital or Syntec meetings.
Or many meetups.
Most French universities and Grandes Écoles (e.g. Telecom Paris but also EPITA or Centrale) organize regular research seminars that anyone can attend. You may need to subscribe to mailing lists or perhaps pay a small fee (a few dozens of euros) to attend them.
Use google to find seminar close to your research interests.
The LIP6 computer science university research library is helpful too. You'll find names of computer scientists easily there.
I am wondering if there is any 'online' seminar site for researchers around the world? Researchers can discuss about their research.
You should consider meeting researchers face to face.
In the Paris region there are many of them in information technology (including at CEA LIST where I work, or Université Paris Saclay, ENS Paris Saclay, Ecole Polytechnique, ....). Since face to face communication is giving more bandwidth (non-verbal communication) than most electronic media. See also séminaire codes sources.
Notice that Google and Facebook have research labs in Paris and they also sometimes organize seminars.
In 2020, research ideas related to software are practically using open source or free software proof-of-concept prototypes (read about TRL and attend Horizon2020 or HorizonEurope meetings; you might meet me there). Perhaps organizations like APRIL or AFUL or IRILL might be a good way to meet persons.
computer science research site
Obviously cs.stackexchange comes to mind
If you are excessively scared to meet people in person (and I am also very shy), consider using the help of some psychotherapist. My wife happens to be one.
PS. You could also send me an email (in English or French) to
firstname.lastname@example.org mentioning the URL of your question, your actual research interests in computer science, etc...