Ok so is Lurking a viable strategy? The answer is more complex than it sounds.

First, we need to differentiate being legit afk from lurking and what it does.

Being afk for rl reasons - means you have no idea what is actually going on while away, and usually need time to "catch up" when you do come on and then need a bit more time to absorb and sort everything out before posting any coherent thoughts. I add " " to catch up because if there hasn't been any posting while you were afk then there is no time needed to catch up as was the case in Convergence fm having less than 5 posts in 12 hours or all the posts being related to a single subject as in the case of Yayap vs Mike.

When someone is afk, I've noticed that person either
A- make 1 mega post with lots of quotes to address all his thoughts in one go (what I usually do) since he went offline
B- make lots of individual posts to comment on posts he feels needs talking about (thus why some people make 5-10 posts in a row all relating to different topics).
C- that person ignores most of what is said since he left off and just continues in game when he gets back online (more common when there is hundreds if not thousands of posts to read and one cannot be bothered)

In both cases A and B, that person gives off ideas related to those topics and his leave of absence doesn't affect the game information wise. Whereas, C can still catch up when other people re-post ideas, quote or even sum up what he has missed.

The biggest impact this has is when someone replaces in mid-game. Because he has so much to catch up on, it is hard to evaluate his comprehension of what has transpired, for example, Glip in Convergence.

Lurking on the other hand is knowing what is going on and actively choosing not to participate in the discussion. Some people think this is a viable strategy since you can't slip when you are scum if you don't post. While this is true, the very act of lurking is detrimental to town and is scummy. The only reason it works is because bad town players lurk too and they blend in.
If everyone lurked the entire game and every day was decided on a CFD with no other information, scum would win almost all the time because town would never form a town read on anyone nor a scum read.
If you are town, it is almost imperative that you participate to give a chance for others not to have a blanket null read on you. Even in the middle of a mislynch, if your reasoning is sound, it will show that you are trying to solve the game instead of not caring what so ever.
If every town player didn't lurk, scum lurkers would be forced to start posting more or be deemed a lurking scum - which in turn increases the chance that they slip something that they shouldn't know or show faulty reasoning for pushing someone - it can expose them much more.
Now back in the day when no one cared about if they were shown to be online and didn't have that little box checked to hide their online activity, it was much easier for me to track down lurkers and identify those that were afk, (thus my reads on lurkers was more accurate back then). Now, its much harder - as I have to find out there online activity meta and guess if there are actually afk or lurking.
If there is a heated debate on a scum and people are pitching in ideas that are actually true - scum do not like to highlight where their scum buddies slipped, thus scum tend to post less or post stuff not related to the current discussion.
Lurking can also be someone posting off-topic posts to distract from the discussion. In convergence, scum hardly did this at all - but town did it a lot with their spam or RP related trolling. Just because you are posting a lot does not mean you are not lurking. If you aren't contributing to the discussion, then you are just a guy in the back of the room not paying attention making noise - noise that we then have to sift through and decide if you intentionally tried to distract people from the topic at hand for scum purposes.

This however doesn't mean you should say everything you think, there is a fine line of giving good thoughts and giving away ideas that scum haven't thought about yet. This is the case of TPR identification, if you have a strong lead on who is a TPR that other people don't know about - either from night feedback/coded signaling, then it is not always in towns best interests in sharing that info due to limited protection resources. It should however be factored into your secret reads and help you narrow down who you can trust. Sometimes giving a blanket scum read on someone you know is town is in their best interests - you only need to expose your secret read if that person becomes a topic for lynch - and I would add, that if there are enough votes to make him a possible lynch. As long as there is no risk of that person being lynched or night killed by a town killing role, then keeping him out of the spotlight is better.

Then there is the issue of pressure voting.. how do you pressure someone to contribute to give you are read if they are just lurking - it is a futile experience as you'll most likely make it to eod with no extra posts from him to give you the necessary info to make the right decision, and you'll be left with the choice of lynching the lurker or voting someone else. While this sounds great if you are scum, if town aren't lurking, then a policy lynch on the lurker isn't that bad of an idea.... but when 50%+ of the players are lurking then you might as well flip a coin on who you are going to lynch.

In short:

Is lurking a good strategy?
As Town - HELL NO!
As Scum - only when there are enough town lurking that you don't stick out. Which brings me back to town shouldn't be lurking so you shouldn't either.

The only things worst than lurking for town is town players spamming and trolling. Which you might as well just policy lynch these players since you'll never get a good read on them. A game with a town full of lurkers, spammers and trolls is an easy game for scum to win. Don't be the guy who makes it easy for them.