Dark side of your blog : when it is a spider (e.g. googlebot) that visit your site... the look of your site could be unexpectedly different.
Casually I noticed some pretty strange links on my blog.
I never added them. I never seen them with Chrome, Safari.
Those links are shown only when I use firefox and this is a riddle for me.
What I mean ...
On FireFox it is present a link : "best way to weight loss in a day" that I never add
Those ghost links are different every time that page is reloaded :
FireFox is not to blame ... I figured out.
I use FireFox in order to develop and for my work I changed the user agent of FireFox in order to mime googlebot crowler.
So what I noted is that when the user agent that lands on the site is identified as crowler on my blog these links are shown. After a little investigation I discovered that Ultimate TinyMCE (visual editor plugin for wordpress) was responsible for that.
Goal of this is to increase PageRank PR[A] associated to page A (let me name as A the page that is associated to the ghost link) : basically more sites are linking page A and more hight is PageRank associated to A (ok isn't so trivial more details here : http://worldwide.espacenet.com/publicationDetails/biblio?CC=US&NR=6285999&KC=&FT=E and on wiki).
More PageRank means more traffic from search engines. So it is not relevant if link isn't shown on a "normal" browser. Instead what it is important is that crawler sees it, follows it and increases PageRank of page A.I don't know if this represent a loss in term of SEO for my blog : potentially from point of view of crawler I have a link outgoing to ... I really don't know to what and the reputation of site associated to hidden link.
Disable Ultimate TinyMCE
Ultimate TinyMCE is a good visual editor plugin so I encourage to use it.
But if you want then you can disable this behaviour ... deselecting :
Develop Credit : Gives credit to the developer in form of a hidden link.
How to change the user agent of Browser
At this point could be useful try to explore own blog/site with user agent that is a web crawler. Really to change user agent could be useful when you need to simulate (with safari for example) some mobile devices (e.g. iPhone, Lumia 920, Nokia ...).
Here link to user-agent for nokia (I use that for my work) :
http://www.developer.nokia.com/Community/Wiki/User-Agent_headers_for_Nokia_devices (this link seems to be broken)
About web crawler and googlebot user agent are :
Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)
A useful way in order to change user agent of firefox is to use this add-on :
Below how I filled for user-agent Googlebot :