'Not single/not looking, wants to date but nothing serious'?

Seen this on a few POF accounts; they're in a relationship, they're not looking but their account is up/ is the relationship they are in isn't serious or the one they would be willing to have with you won't be?

Ultimatly what that does that mean? (No I'm not considering these guys but I've seen this a few times)
'Not single/not looking, wants to date but nothing serious'?
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