a (or the) world of
is defined in Oxford as follows:
A very great deal of.
‘there's a world of difference between being alone and being lonely’
‘a bit of country air will do her the world of good’
I think the world of should be treated differently, so I'd like to focus on a world of.
Although the Oxford Dictionary says a world of means 'a very great deal of' and the phrase should be singular in that meaning, I've seen a world of followed by a plural noun. And when it's followed by a plural noun, I think it often means 'a great number of'.
The problem is, there is conflicting evidence as to whether a world of followed by a plural noun is singular or plural:
And with the collapse of those ''walls'', a world of opportunities is opening before us.
(SADCC at Ten, Address to the Tenth Anniversary Summit, Gaborone, Botswana. 24 August 1990. Published in The Missing Headlines: Selected Speeches, by Emeka Anyaoku)
You've not yet developed notions of what you can and can't do (or what you should or shouldn't have done), and a world of opportunities is opening before you. (Confined Minds, by Raychelle Meyers, p. 25)
A world of opportunities are out there for you. (The Strength of a Woman: Transformed for Greater Impact, by Claudia L. Roach)
Since 'a world of' here means 'a lot of', I'd think the plural treatment is more frequent, but the opposite seems to be the case. There seem to be more instances of the singular treatment.
So should 'a world of opportunities' be treated as singular?
How about this case?
This morning saw Jay-Z release his surprise new album ‘4:44‘ across all streaming services except Spotify – and a world of fans take note of the freestyle rap by his daughter Blue Ivy Carter. Check out the best reactions and the lyrics below. ("Fans react to Blue Ivy’s freestyle rap on Jay-Z’s ‘4:44’", by Andrew Trendell, NME Music News)
Here, too, 'a world of fans' I think means 'a lot of fans', but is followed by a plural form 'take'. Do you think this is incorrect? Or should it be treated differently? I for one think the plural treatment is correct, because it's the individual fans who take note, not the world itself.
This question is not solved by an earlier question, "Is “an ocean of flowers” singular or plural?", where only two answers are provided and no answer is selected.
Moreover, the answer with most votes (2 votes) in that question seems to approve the plural treatment of 'an ocean of flowers', whereas my research about 'a world of opportunities' suggests that the singular treatment is more often than the plural treatment.
Most importantly, the earlier question and answers do not address cases where "an ocean of" is followed by a plural noun denoting people, which is raised as an important point in this question.