Say I am studying a particular topic (CS theory) for my work/otherwise and I come across a great resource on the topic. Is this site a good place to share the resource (link/ppt/pdf), or maybe you can recommend some other site ?
This site (and the Stack Exchange network in general) is a questions and answers site. Questions generally fit the mold of ”I have a problem, how do I solve it?“. The problem type can be varied — “how do I make my car start?”, “how do I prove this theorem?”, “how can I understand this text?”, etc. But sharing resources doesn't fit. Stack Exchange is not a link collection — we greatly frown on answers that just say ”go read this other document“, we expect answers to have actual content. So sharing a resource via a question and answer pair would only be appropriate is that resource solves a problem and the answer explains the solution — for example, “how do I prove this theorem?” → “here's a summary of the proof published in <article>: …”
You can post pretty much anything in chat as long as it's related to the site's topic and generally appropriate¹. Just don't overdo it — chat isn't a place for spamming.
There are sites on the web that are dedicated to links to resources or have designated areas for that. Reddit comes to mind: Computer Science: Theory and Application, Algorithms, CS education, CS career questions, … Hacker News is another (at least for sufficiently applied topics).
¹ For example, illustrating a compression algorithm with an X-rated picture would not be appropriate.
a great option around here (the stackexchange world) is a relatively newly introduced community blog system on stackexchange. it looks like about 21 se sites/communities are blogging. more info on starting here. the sites may work on a somewhat volunteer system to create blogs. of course you can always start your own blog too. another option is "guest blogging" on someone elses site. some people on here [incl mods] have their own blogs.
also the CS chatroom has been active over the last few weeks. its also easy to start your own public chat room and post to it regularly if you have material over an extended time. the pages are public and URL/web page accessable.