Both contain characters cursed with immortality. The gods have physical incarnations (Or one at least in Long For U 2). There is a "reaper-like" character in both dramas as well as a goblin character (They're both the same person in Long For U 2). Overall, both similarly enjoyable!
Both have an immortal fall in love with a human. There is conflict in knowing that they will never age so this sets the pacing when do come across that one person who intrigues and makes them 'fall' in love. LFATM is a short drama so easy to marathon, the characters are fun and likeable. Immortal leads in both, face inner conflicts in trying to make the right choices about love, and their own personal purpose of the life they live.
Both dramas have the god meets human theme and the executive producer of this drama is Goblin's screenwriter. By the looks of the poster, they look like the younger versions of Kim Shin and Eun Tak.
Search: WWW in my view was a little bit influenced by the classic and original fantasy story of "Goblin" with some elements more tied to the background scenes of the story life, like rain, nature itself and the intense feelings that surrounded the story as a whole with strong and versatile characters.
The big difference is that it's centered on a more modern scale where women from the search engine industry with strong careers and personalities challenge themselves to fight against prejudice, injustice and eventually the corrupt society itself!
Both deal with deep Life/Death questions.
Goblin is a drama with same leads/chars throughout all episodes like it usually is, while Loss:Time:Life features different characters per each episode / is an anthology series
Goblin also has romance, LTL only deals with the life/death part