Show & Episode:
Supernatural – Hell House (S01E17)
When investigating a series of murders in a seemingly haunted abandoned cabin, Sam and Dean run into a pair of paranormal investigators. The investigators run a website called HellHoundsLair.com, which contains reports of paranormal instances.
WHOIS shows the domain is currently registered by Warner Bros. Entertainment. According to Archive.org, it used to point to a website similar to the one displayed in the episode. There wasn’t a forum, but it did contain links to a number of legends and the ability supposedly to submit your own stories.
The domain has since been redirected to point to the official CW network website.