Long answer: internet services became easier to use for non-technically savvy people. It's no coincidence that as internet access broadened, sites like Facebook gained popularity because they gave people premade, customisable pages that could allow them to express themselves to others and engage in discussion.
Early facebook was so different. It had all these weird customisable mini apps that embedded in your page. Like "hatching eggs" where someone would "give" you an egg and you had to wait to see what hatched out of it.