I don't understand this guy (same old story, I know...)

Hey there! I have a situation that requires some manly insight.
So, here's the story:
1. A guy (good friend of a good (girl)friend of mine) starts following/befriending etc. me on social media, although we've never spoken face to face before. He liked my posts, I liked his, it seemed quite right, you know...
2. He asked my friend if I'm a good girl, cause he's into me and he doesn't want to suffer. She told him I was OK.
3. So he finally starts chatting with me. We got along very well, but at some point, he started drifting away.
4. I mean, he hasn't disappeared altogether, but he has sudden outbursts of flirtiness, then nothing for weeks, then he sends me music or movies suggestions, then he's absent again, and so on and so forth.

Am I still under his radar or I am being friend-zoned? What do you think? Should I pursue something with this guy - and how - or simply move on?

Thank you so much!
Georgia

i don't know.. tell us more aobut him. is his life or profession as such that he gets busy for bursts at a time or not?
what is his personality like?

you've been talking to him so you have learned something about him right? so apply what you have learned to tell you if this is logical or illogical befhavior.

there is no "golden rule" for everybody... so our job is to assess what they are like whether we're around or not.. and then compare that to how they are around us - and typically we have our answer when comapring the too. so it's quite simple.. to figure out "wha'ts going on with person A" you have to get to know and undersatnd Person A first. (not go by what we wish them to be to us).

Make sense?

Thanks! It does, theoretically, but the fact is I don't know him that well. My friend said he's a good, serious guy. And, as far as I know, he's not particularly busier one time more than other. Early on, he kinda implied that we should go out sometime and know each other and I agreed, but he hasn't mentioned that possibility since, although he complimenting me from time to time. Several mutual FB friends of ours have noticed something's going on, from the way we interacted recently (therefore I am not imagining things). But since dating is out of the picture (it seems), are we just people with similar tastes that chat from time to time? I know I should compare how he is in general with how he is with me, but we haven't had the chance to know each other that well.
And another thing: should I make the move and ask him out, or am I about to make a fool out of myself? Sincerely, I am really infatuated with him, who wouldn't like someone who likes them in the first place and with whom has a certain number of affinities?! And the fact that I know there's something to lose makes me play different scenarios in my head instead of just waiting and seeing, I guess.