tag1,tag2,tag3,tag4,tag5 (comma, no spaces) or tag1, tag2, tag3, tag4, tag5 (comma, single spaces) or tag1 tag2 tag3 tag4 tag5 (just space) or
tag1 (new line) tag2 tag3 tag4 tag5
?
What about when a tag contains several words: "word1 word2 word3" ?
Basically these are for search engines. I don't think delimiter matters too much to the morden search enginres. I would use comma with single spaces for human readablity.