Append in field vs. Details table

[Idahomail]

Hello, 

I'm trying to look at the best way to set up 2 different projects that have the same question. 

Both of these could be solved with a 1 to Many relationship with a details table, but I'm wondering if a single field in the record that I could append and delete from would be more helpful (and less records)

Note: I only have 4 users and do not need this to scale. 

1. I'd like to add keywords to a database containing photos

PhotoID 
Container (reference)
Keywords 

2. I'd like to list the users that have viewed a record at least once. 

- I am not interested in how many times or when they visited. I just want to know who has seen this record at least once.

I think I'm just afraid, particularly in #1 of a giant table connecting keywords to a record, when it would seem easier to have hem stored in the record.

 

Thanks in advance!