I don't hide signatures. I've definitely been influenced by signatures here on the forum in the past, and I'm sure that's true for everyone that doesn't hide them. Being influenced even by a advertisement isn't always a bad thing. I've discovered some quite cool projects over time, and I'm sure there's been instances that people have found services that appeal for them, well its a given really.
I remember reading a post by someone a long time ago who talked about the benefits of signature campaigns. He was advertising a company and had a referral link in his sig. After a while, he checked his stats and noticed only 1 or 2 clicks. Campaign-wide, it wasn't any better with the other participants. But the campaign still kept going.
Depends on the type of participants that they had as a data set. However, a referral link isn't a catch all. Advertising doesn't always work for direct links, however getting the product in the mind of a potential customer is what you want to do. I tend to be quite good at blocking out advertisements on TV etc, but I've even noticed that Sponsored videos on Youtube, while I haven't used the infulencers direct coupon code, they got the product in my mind, and when I needed something like that, it was that company I thought of.
So, there's direct advertising, and indirect. We know advertising works, because I bet the majority of this forum are aware of the companies that regularly advertise through signature campaigns. In fact, the very lure of getting paid to post, is an advertisement, because it creates brand loyalty. If x company pays you to post, and you use them, you're more likely to actually use their service over a competitors.
Therefore, even if you don't get direct referral link clicks, the advertisement itself is still working. I've even had messages asking me about the advertisement in my signature in the past. So, people are definitely noticing them even if they aren't clicking them directly. We have to remember as well, not everyone will know that the links are clickable.
Personally, I don't remember ever clicking on a link in a signature campaign and I believe that most other members on this forum also don't click directly on those links in the signature.
This might just be because none of them interest you. We know advertisements work, since TradeFortress built their entire online wallet out of the advertisements. It become widely used, and I would assume that this was majority built on his signature campaign they were running at the time.
I've not clicked on many, but I have. Especially, more personal projects. I'm visited quite a few personal websites of users here. A few years ago, it was more common to use the signature for either personal projects or personal interests. For example, I used to have a Slackware link, because at the time I was tinkering around with it, and enjoying it.
So, for a advertisement to work it needs to hit the right audience, and the number of clicks a referral link gets doesn't necessarily indicate how good the advertisement is working. Its an indication, but because most people would likely digest that advertisement subconsciously or indirectly look it up, then it only catches a few, and isn't a catch all.
I can't imagine sig campaigns are completely useless for the project/company that runs them, else they wouldn't do it, especially not the longer-running ones like Chipmixer, 777Coin, and Yobit and secondstrade some years ago. If they're run by people with some actual business sense, they'd be analyzing how much revenue their advertising brings in and whether it's worth it to run a signature campaign.
We know advertisements work. Edward Bernays taught us that the human mind is very susceptible to information, even if its completely wrong propaganda. If anyone hasn't read his book, I recommend it to get some insight on how governments control its people. However, going back to if advertisements work; they work very similarly to propaganda, and both are used to influence the population. Just think of it, anywhere you go on the internet, real life, or just anywhere you will see probably 100s of advertisements a day. You might not register all of them consciously, but you've seen them subconsciously. So, the next time you want something related to that advertisement, you'll remember it.
There isn't an argument to be found when arguing against the effectiveness of advertisements. We know advertisements work, in fact we are now more aware they work, since our platforms like TV, and even Youtube are becoming more, and more advertisement friendly. Youtubers have found out that, they can earn more money, and companies can earn more money by putting a sponsored video by the infulencer inside the actual video, instead of via Youtube ad breaks, because its more personalized, and the followers of that person are more likely to take note of the advertisement. This is the same for this forum, if you particularly like someone or someone's content on here, you are probably more likely to be interested in what they are advertising.
Take theymos talking about Grin coin, now he was very cautious about clearly defining that he doesn't necessarily recommend investing into Grin coin, but was more excited by the technology behind it, while clearly defining his opinion on the rather big short comings. However, take a look at how many people rushed to the announcement thread once Grin coin was officially accepted on Bitcointalk for Copper membership. Now, most of them would have likely never heard of it or at least it would have taken years for them to even take a whiff of the name GrinCoin. However, that announcement thread was flooded with all kinds of users, even those that probably don't even visit the altcoin section.
Just to be clear, I don't think theymos was advertising GrinCoin (at least not directly), but you can see the impact that someone who is maybe looked up too, can have on others. So, advertisements in signatures work in the same way.