I can somewhat relate to your situation. I am 22 and my wife is 23. We've been married now for 9 months. Not a long time, but we have been together for about a little over 2 years now. We spent 6-7 years though communicating online.
I have never had any trouble with communication between one another but my method was to help her by helping teach her new things that she never had interest in. I'm not sure of it being the other way around but maybe if you educate yourself in some of the things he likes?
A big one for guys would be sports. Now i'm not saying you have to be all up into sports but just do some research in whatever sport he enjoys and throw in some of your two cents about it.
For example, i'm a huge addict and fan of professional boxing. Now if I mention some of the biggest names out there in boxing like Floyd Mayweather, Manny Pacquiao, Bernard Hopkins, she would look at me with a clueless look. Her method of fix was to sit down and watch boxing with me. Since I knew she doesn't know much about the sport, I explain things to her so she can understand what's going on.
I am fascinated with the idea and I adore her effort to do things like this for me! Another big one is watching my type of movies versus her chick flicks. I appreciate her effort and she will ask questions and I am more willing to answer her about movies.
I think a good way to help make topic is just ask more questions. Learn more about your significant other and then with those answers try and research or gain interest in those fields of topic. As the other poster had said, politics and news are good areas to discuss as well.
When I come back from college in the mornings, my wife always asks me how was school and i'll let her know but she has accommodated to asking me about things within school whether it be what we covered for the day or transition to politics, plans for the day, and so on.
My last suggestion, is not really a suggestion but just personal experience, and I am in no way condoning it as a method to create discussion, but the biggest thing that keeps us on our toes and constantly having things to talk about and share times together is our 1 year old daughter. When all else fails, our daughter becomes the center of attention! Now I know this is way far fetched but later on in your guys future when you two are ready, which I don't want to indulge in your personal life in no way, this might be something that will help create discussion and make progress worth while in the relationship.
Like I said though, i'm not condoning this as a solution because a child becomes a huuuugeeeeeeee responsibility and for me, it set me 5-10 years backwards in education and finances. So my point is, when things are in the later future, and if it is a subject that arises, this might also be a fixer to such a situation.