It means that they have tailored their curriculum around self defense, street use, and NHB. BJJ schools who are mostly gi or gi only usually enter a lot of sport jujitsu or grappling only competitions.
The gi stuff teaches some good collar chokes that you may not get with the no gi school, but I think you will be happy with your choice anyway. I think the no gi stuff is more practical, but that's just my opinion.
Please Scroll Down to See Forums Below 
