I know it is possible(the title), but I wanted to know how is it. This may look like a request, but I wouldn't call it like that. I just want to know how is it possible, with which function or object or API or modulescript... What I actually want to do is getting most popular places' information like total player counts, current player counts, place's owner, last updated etc. Since HTTPService cannot be used on Roblox's website, what is the way to get such information?
You do need to use HTTPService. You need to use a secondary site that will request the information from Roblox for you; see http://wiki.roblox.com/index.php?title=User-created_web_APIs (though the only one present at the time of writing does not appear to be working).
If you can't find a similar API elsewhere, you could make a server that did this yourself, but you'd either need to host the server on your computer 24/7 or rent one online and in either case you'd need to know how to code it.