For me, it would have been the Internet in 1990. On it, specifically the bulletin board soc.motss, I discovered discussions of homosexuality and all sorts of aspects of it, updated daily. It covered films coming my way, radical political positions, debates on company policies, being out or not out, AIDs...
Most importantly, it was discussions by and between lgbt people, not some other media talking about lgb people. The only other media by lgb people that I had seen before that was an article or two in student union magazines, and always about coming out. The Internet discussions were much more interesting and informative than that.
And I could watch safely for a few weeks until I felt confortable chipping in.