Blogs went largely unchallenged until Facebook reshaped consumer behavior with its all-purpose hub for posting everything social. Twitter, which allows messages of no longer than 140 characters, also contributed to the upheaval.

No longer did Internet users need a blog to connect with the world. They could instead post quick updates to complain about the weather, link to articles that infuriated them, comment on news events, share photos or promote some cause — all the things a blog was intended to do.

Indeed, small talk shifted in large part to social networking, said Elisa Camahort Page, co-founder of BlogHer, a women’s blog network. Still, blogs remain a home of more meaty discussions, she said.

“If you’re looking for substantive conversation, you turn to blogs,” Ms. Camahort Page said. “You aren’t going to find it on Facebook, and you aren’t going to find it in 140 characters on Twitter.”