Being careful with links

You come across a webpage with something useful you want to share so you Post, Tweet or Blog about it on your Social Media of choice. Everyone does this, it's what the Internet is all about.

Yes, but... There always seems to be a "but" doesn't there.

We all want lots of people to visit our webpages - to read good advice, buy our stuff, whatever. To do that they have to find them, and that means Search Engines.
One parameter that Search Engines go by is Links. If lots of people are linking that means they found what they wanted so most likely other people will find that link useful too. Of course they might be saying "I just found this horrible webpage" but let's ignore that one.

So let's suppose you are a conartist, a quack, a fraud, whatever - you are offering something that isn't legit. Your website looks good, you put in all the right phrases like "morphic resonance", "quantum orbs" and "100% natural organic", now you want more traffic. Here's one way - add some pages that aren't nonsense, just general good advice like "eat more vegetables". You don't have to research this stuff yourself you just use someone else's work, with pictures and a video if possible, and maybe put "Source" at the bottom. Like this:
http://news.msn.com/science-technology/
I'm using MSN as a template example. Look carefully and you'll see that the articles come from news agencies or are writeups of information from elsewhere. MSN staff are reporters not scientists, which is fine and good because that's their job. Nevertheless it's always sensible to check the Source out as reporters can slant stories, oversimplify them or simply make errors.

So, I want to find news about Vegetables, I do my Google Search, find what looks to be (and actually is) a rational article and post a link to it. What's the harm in that?

The article was on the quacks-r-us.org website. By linking to it I just helped Dr Evil PhD(Arkham) with his evil plan to stop people vaccinating their kids and buy his homeopathic bottles of magic water instead. OMG. I just killed someone's child!
Now I'm not going to be fooled by Dr Evil and nor (I hope) are you, but those links help more gullible people than us find him. Please don't do it - use reputable Sources for your good advice.