[Scythe Massakur]

One of my players is making her first ever character and is having trouble figuring out the difference between some of the knowledge skills that I as a first time DM cannot answer. Specifically, she is trying to figure out what the Matrix and Hacking specializations of the Data Haven KSs are. I made a guess, based on what I know, but I'd like a more concrete answer to give her.

[Stainless Steel Devil Rat]

Generally, Knowledge skills are 1) whatever you want them to be and 2) whatever the GM doesn't kibosh.  A detailed answer is slightly different depending on the edition you're playing.

6th edition: Knowledge skills don't have specializations.  Just take whatever you want.  Data Havens would be a skill that applies to knowing hacker hideouts and so on.

5th edition: (I suspect this is the edition you are playing, since they DO have specializations).  Just like the knowledge skills themselves, their specializations are whatever you want them to be.  Note that all the active skills are simultaneously knowledge skills (see the substituting skills sidebar, pg 130).  So if your player wants to have knowledge skills relevant to "hacker stuff", simply having the Hacking active skill should cover it already.

[Scythe Massakur]

I appreciate your answer. I'll utilize that mind set going forth.

[FST_Gemstar]

They are just a way to on character sheets give more uniqueness and personality to characters that often end up with similar stat blocks. I would advise folks be as creative and specific as possible with knowledge skills, and as a GM, be flexible and mindful in folks using an appropriate skill to offer something interesting and unique in play. When calling for dice rolls, penalties/bonuses, or necessary hits, keep how specific and interesting a knowledge skill is

[Glyph]

Generally, the narrower a knowledge skill is, the more you know about a specific thing but the less you know outside of that narrow scope.  Broader knowledge skills cover more area but more superficially.

For instance, you are prodding your mind for information about simsense star Foxy Fiona.  If you have the knowledge skill "simsense stars: 1", you might know a bit of information about Fiona.  IF you have the knowledge skill "Foxy Fiona: 1", you would probably know her short bio, sims she has been in, and at least some of the latest gossip about her.

On the other hand, while the person with the broader knowledge skill would know comparatively less, he would know these snippets of information about Foxy Fiona and other simstars.  So if you were wracking your brain for what you know about simstar Buddy Fine, you would at least have some general information about him, while you would be mostly out of luck if you only had the knowledge of Foxy Fiona (maybe you would know that he starred in two of her films and dated her for about a month).