These days you can not piss in the wind without hearing about sites crashing or being penalized by google, and it is my belief that google has setup a system for starter & middle class sites to fail! Yes, I am aware that there are dishonest webmasters out there that deserve to be punished to the other side of the galaxy, but I am not talking about them; Google treats everyone the same, honest, dishonest, it does not matter, and if you are honest, then google punish you the same. Joe Blow sets up a site, over time, it looks like his site is going good, so good that his competition knows it, and they do not like joe blow simply because he is taking more of their business away everyday or there maybe some feud between the sites. So competition runs out and orders a few fiveer gigs, and you know the link spam packages that I am talking about, and sends 100k links to joe blows site every week for a month. Think google cares? nope, next update, or two, joe blow is gone from the world, and he is reading all these articles online on "monitor your backlinks" - "disavow the bad ones" bla bla.... now joe is thinking, how the hell am I am going get rid of 100's of thousands of spam links. Google may have been noble trying to weed out low quality content or links, but they failed to realize that the competition can take out any low fruit site they see fit, and before that site ever reaches any decent level of having any type of authority. The solution: Since google can already tell the difference on low quality, then why penalize sites at all? Why not just discredit the value of content or links to having any effect at all? If not, then why even start a site today, then tomorrow, or even next year, your competitor(s) are sending 100's of thousands of links to your site.... This is the way I see it.....
I sincerely believe that you've made such an excellent point in this post because there are many people who've fallen victim who've done nothing wrong. That's the kind of deceptive environment that webmasters find themselves in, so if someone doesn't like you site in the sense that it is taking their business away or they want to knock you out, they point junk links to your site in order to harm it. I think it is something that Google has to find a way to address that issue.
Google has been burying sites in the SERPs for no reason for many years now. I have experienced it with every site I ever created. Back then, it had nothing to do with spam links and maybe it still does not. Funny thing is that a week or two Google buries my sites in the SERPs where nobody will see them (after they previously ranked where they would get some traffic), Google sends me an email trying to get me to pay for advertising to replace the traffic I lost from Google. Every visitor Google's search engine refers to you is a visitor you do not have to pay Google for. Google does not like that.
Yup. Google likes to make money. Google does not like you to make money (unless of course you pay Google your money).
I have the same experience. One of my sites is a commercial site (for brick and mortar business) that ranks relatively high for our keywords of interest and we do use AdWords there as well. Yet, every time our traffic/SERP drops (typically for no reason) I get a call from Google AdWords asking whether we want to discuss some campaign opportunities... I assume this is more of causation than correlation :-(
My friends site was exactly the way you explain she didn't knew anything about seo all she did way putting articles on her site on a weekly basis. Then received an email from the big G, the thing she didn't knew where to start because she had no knowledge of backlinking worked and just gave up the site all together.
Huh?? That doesn't make sense. "Then received an email from the big G" What email? Why would getting an email mean she gave up on the site?
Good point. Bad intention can ruin your link profile. Personally, my problem is not so much with the links, but a bunch of junk traffic that's coming to me from various .ru, .ua and a bunch of spam links. Tried disavow, but even listing and detecting these links takes ages. I don't know whether these sites find everyone or, whether someone with bad intention is sending me "gifts".
This issue was actually raised by a lot of people way before the last big Penguin rolled out - that Google had to also find a way to tackle Negative SEO. Months later and a grand rollout of the algo update and absolutely no change on that field...Google can just shrug their shoulders and walk away, its not like they are not way past trying to convince people they are not evil