I have read that lending threads they are mostly not active as gambling threads are active. Secondly there are more borrowers then lenders and one need to be very careful with collateral.
What type of collateral one should accept if you are starting lending on bitcointalk.org?
If you've been observing the patterns on the Lending subforum, it's mainly requests from trolls that are not serious or just plain scammers.
https://bitcointalk.org/index.php?topic=5368349.0They would post some sob story, then upon being called out by the seniors, start to show their true colors. Happens with the sock puppets or alt accounts.
If you're a lender, the safest and easiest would be highly liquid crypto (e.g. ETH/ BTC/ LTC). Doesn't take too long to receive and miles better than bank transfers.
Secondary would be physical items, but appraising them is difficult because of the shipment time and also the need to find the right buyer.
Accounts, very rare because they could almost always be recovered.