I have recently noticed that when i visit certain websites, there are usually links tied to certain words. I can’t find an answer from where i have looked, and i have noticed similar trends from several websites, but especially my own.
Is this a programming, hack issue that can be solved by adding specific code or is it my hosting company doing this, or does it mean that someone has gained control to my ftp portal?
Please see the image below of what i mean and any help would be appreciated.

They’re called in-text contextual advertisements, though they probably have many names. Here’s a wiki article about them:
http://en.wikipedia.org/wiki/In-text_advertising
I don’t know if Google offer these (due to how annoying they are), but I’m pretty sure AdBrite does:
http://www.adbrite.com/mb/exchange_publishers_ad_formats.php