Everyone who publishes anything (even if they don't know it) loves being mentioned on other websites. The longest time ago when I wrote a personal blog for friends about whatever came across my mind we had link sharing; you link to my blog and I'll link to yours. The practice amongst friends or readers conveyed a sense of trust in the content of the other site which was picked up on by Google and became the backbone of PageRank. So, forward ten years into the future, spammers try to increase their rank on searches by having others link to their site (or just creating lots of sites themselves and linking them all together).
People still love to be mentioned on the web and it surely says something for your own personal brand when other people see you mentioned on the web. Calling someone out on your blog is a good way to get their attention and maybe even a link back to your site. Add in some psychology that says that if you do something nice for someone else, they feel compelled to do something nice for you and you have an exploitable situation. Enter bad guys. They're thinking that if you linked to enough people from some semi-spammy site, you could get enough people to link back to you to gain some search cred.
Okay, enough theory. There's a site out there called Accredited Online Colleges (I won't link to them because I don't trust them) and they're essentially a front for another site that pushes online degree programs1. There's lots of repetitive links and they're clearly optimized for convincing search robots that this is the place to go for an online college search. Unfortunately, they have no valuable content.
This is where our ideas behind linking to others come in. They do have a blog where they (you guessed it) link to twitterers and others sites on bombastic lists such as "100 Amazing Scientists You Should Follow On Twitter".
Yes, I am listed as an "Amazing Scientist" on that list. No, I don't think that it's a sincere appreciation of anyone on twitter.
The blog is designed to get people to link to it because people love being linked to. And it works! The bit.ly aggregate link has been clicked more than a thousand times. From all these links, they get a better search position and make more cash referring search users to the actual appropriate site. It's the classic scenario of stacking the space between manufacturer and consumer with middlemen that drive up the price (or, in this case, the clicks). It's not OK because it pollutes the web.
The scientists on twitter make for a really interesting community of people and lots of great chatting and trading of ideas goes on there. @flyingjenny is a really fascinating look into how NASA works on the inside, even moreso now that we know the fate of the Shuttle. @BadAstronomer is, well, the Bad Astronomer and you probably need no more reason than that to follow him on twitter. People that you could never even hope to communicate with on a personal level are out there, responding to tweets from regular people (@neiltyson, @garrettlisi and @seanmcarroll come to mind).
So do yourself a favor and check that link before they you link back to it... especially if it's just a passing mention of you. We're not link whores yet.
1 Do I universally condemn online degree programs? Of course not, I'm railing against the method which this site uses to gain links and popularity, not the content itself.