Fetlife bills it's self as the #1 walled garden social network for people in the BDSM/kink/fetish community.
Their security sucks, and the site is easily crawlable and it's content somewhat archiveable.
Grabbing someone elses images
Use fetscrape it's easy to set up, but is currently being worked on.
Grabbing someone elses videos
Theres a site that does this and you don't need to pay to get access.
Exporting your own Fetlife
MayMay has done a ton of great work with regard to FL, but theres others building on what maymay did