Are certificates like achievements?
Nope, not even close. My guess when I read the post from CCP about EVE Online's new Certificates was way off the mark. I thought CCP had caught Tome of Knowledge fever like some other game (World of Warcraft I'm looking at you and your achievements). That is not the case though. In an effort to simplify and streamline the gameplay, CCP tasked their New Player Experience Group with trying to "smooth off the hard corners of the first few weeks of gamplay." This is something game devs should always be looking to improve, so it's nice to see a developer actually doing something about it. The new Certificate System is essentially a display for the building blocks of skills your character has acquired. More precisely:
"A certificate is a thing that says you have certain skills, and can require other skills and/or certificates as requirements. They're shown in the character sheet and have their own browser window where you can navigate around the certificate tree. You can show them to other people if you want. Certificates are not mandatory and do not give you any bonuses or other special abilities."
If that doesn't clear it up for you, stop by the now subscription free My EVE area to read it in full (and see the screenshot walk through).