I belive this is normal coz i've heard on one of my friend that some of the ICOs as of now don't prefer to advertis here at bitcointalk. I don't know bout the reason but as you observe some of their bounty campaigns are posted in Mediums right?. Maybe they are now using some alternative channels to market their ICO which will be bad for the bitcointalk bounty participants and also for the bitcointalk community i hope it's not about issue of reliability when it comes to promoting ICOS.
There are quite a few that don't view the forum as being a viable way to promote their ICO, I guess for them they see it as either too much effort or just that the target audience isn't great as it's a lot of spammers etc. Many now choose to do targeted advertising through facebook etc and I've yet to come across a coin advertised on facebook that hasn't had great success in their ICO.
Yes, because FB is like any social media the best way to promote a scam. Once a community there has accepted it, they're gonna believe in it. Why? Because people who live on social media do not understand the importance and the definition of trust. Those kind of things disappear from one's perception if social relationships are build and maintained by a mouse click. Just showing your face, talking in an interview and stating that you are against scams (how terrible they are!) is more than enough for a lot of people to base their trust on.
And they get extra coins from the bounty/reward program of course for promoting the scam. It's a win-win. Or well, it looks like that. After all the private sale is the real jackpot, which becomes more and more impossible to get into because there's conspiring among whales. Any coin listed since last Jan18/Dec17 that doesn't take into account whales trying to become intermediate token distributors, by hoarding tokens for >20-40 ETH and then price fixing for example, those ICO's arouse great suspicion and it might not be unwise to avoid them (even though the price surges sometimes enormously, because exactly that is the foremost method of skimming currency from the big heap, by riding the waves you self create). Especially suspicious when the whitepaper states that the team is all about fairness, equal trade, no monopolizing, unbiased token prices, world peace, etc. If something like that is stated in a whitepaper and the token sale shows otherwise, even a tiny tiny glitch, and no posts/info about that for longer than a day? Then the team isn't taking their project serious, because if you're into the blockchain technology and hold a multi-million dollar ICO, then you're online every day, probably even 24/7, and you don't wipe your ass with your whitepaper.