There are few active sites for Lovecraft-related discussion. Because of that, a couple of the links below are archives of once-popular forums.

Forums

There is just a small handful of web-based forums that provide opportunities for discussing H.P. Lovecraft and his works.

H.P. Lovecraft (Reddit)

This subreddit is one of the few easily-accessed discussion forums about Lovecraft. It was created back in 2008 and has over 250,000 members.

H.P. Lovecraft Forum (Chronicles)

One of many forums on Chronicles, a science-fiction and fantasy community site. It has over 450 threads going back to 2000.

H.P. Lovecraft Forum (Horror Forum)

Just one of numerous horror-related forums on HorrorForum.com, it has just over 50 threads going back to 2009.

H.P. Lovecraft & Cthulhu Mythos Forum (via the Internet Archive)

A defunct (but archived) threaded message base that was active from 2002 through 2021.

The Eldritch Dark Forum (Boyd Pearson)

Dedicated to Clark Ashton Smith, though Lovecraft is also frequently discussed.

USENET Newsgroups

A few USENET newsgroups were devoted to Lovecraft and his creations. Unfortunately, most of them began to decline in the late 1990s and have since been taken over by spammers. However, Google Groups has archived them and many of the old posts still make for informative reading.

alt.horror.cthulhu

This was the primary newsgroup of interest, with topics of discussion including just about anything related to Lovecraft or the Cthulhu Mythos. See the Alt.Horror.Cthulhu FAQ by Donovan Loucks, webmaster of The H. P. Lovecraft Archive.

alt.horror

Lovecraftian topics showed up frequently in this newsgroup dedicated to a broader range of horror. See the Alt.Horror FAQ by Christopher Nauta (via the Internet Archive).

alt.necromicon

This newsgroup was theoretically devoted to discussion of Lovecraft’s Necronomicon, yet its traffic was slight. The misspelling of the newsgroup’s name was deliberate.

alt.necronomicon

Finally, someone got around to fixing the spelling of this newsgroup’s name. Like the other Necronomicon newsgroup, the traffic was slight.

alt.horror.shub-internet

An odd newsgroup whose exact purpose was unknown to any but the secret initiates...