A few years ago, when Avi Moskowitz wanted advice about which highchair, stroller and car seat to buy for his first child, he didn’t turn to Consumer Reports or let his wife handle the research. He posted on Daddit, a part of the social networking site Reddit that was formed in 2011 to meet the growing demand of fathers seeking their own cozy corner of the web.

“On Daddit, you get the geekier side of the Internet, where people have done technical research about why this product is better than another product, but I think it also shows that dads are taking on more roles and responsibilities when it comes to parenting,” said Mr. Moskowitz, 27, who works at a security technology company in Ridgefield Park, N.J. Now, he also volunteers as a moderator for Daddit, which has more than 34,000 subscribers — almost twice that of Mommit, Reddit’s site for moms.

Copious evidence online suggests that dads want their own space there, whether public or private, to talk about their larger roles in the family (and to sometimes joke about them). “Daddy bloggers” have already earned large followings. But now there is also a growing number of Internet communities, networks, forums and email lists delving into the joys, trials and even public-policy aspects of being a father.

“No one teaches you how to be a dad,” said Bre Pettis, 42, a New York-based entrepreneur who turned to an invitation-only email list of hundreds of fathers from the technology and media worlds, called Nuevo Dads, when he had a harrowing experience with his premature daughter in the neonatal intensive-care unit.