I guess it depends on where you live.
In the UK I haven't really seen any promo at all, except for the advert played in full on TV once, then a badly edited version of the advert one morning last week.
No posters. No ads on the net or in magazines. No radio ads. If I wasn't an MJ fan I would have literally no idea that there was a new MJ Halloween-themed album out. The ad I did see on TV last week didn't feature MJ's name and only the tiniest snippet of music - probably around one second! Not enough for anybody to recognise unless they were already familiar with MJ's work. As a promo piece it was a complete waste of money.
I get the feeling the promo's been better in other countries, but as for the comparison with other compilation album adverts - I see some compilations being advertised all over the place so it's hardly possible to miss them. Scream?? Not at all.
Anyway, it occured to me the other day that the MJ Estate may messed up with the album.
They say they want MJ To take over Halloween and this year they have shown Thriller 3D to very limted audiences at film fesitvals - the general public won't get to see it until next year so there's been little promotional benefit to the estate. If there's a wider release next year they should hopefully reap some of the reward for the work put into it. Also, there is the cartoon in some countries - not in England though.
When the album was announced many thought it was primarily released to accompany the cartoon (or vice versa) but it doesn't quite feel like that is true, and maybe that was never the strategy but maybe it should have been (hear me out

).
If they want MJ to become ubiquitous with Halloween on a wider level than just thriller, they need to make sure that MJ songs can easily be found when searching for Halloween playlists, but the album is called 'Scream'. I can see why they did that - it includes 'Scream' and MJ liked to name his albums after one of the album tracks. MJ didn't have a song called Halloween but in my humble opinion, the album would be much easier to find around Halloween time if they had called it "Michael Jackson's Halloween". When anybody is searching for a Halloween playlist on their favourite music service or store, albums or songs using the key word "Halloween" are most likely to feature in the search results. The title "scream" is far less likely to appear. Also, calling the album "Michael Jackson's Halloween" would tie in closer with the cartoon. A much more cohesive approach and the two products appear as part of a unified strategy, rather than separate as they do currently.
Do you think Mariah's "Merry Christmas" album, which is a strong seller every year, would have had the same success if it was called (for example) "Joy to the World" and didn't show her in a Mrs Claus outfit on the cover? I doubt it, but the MJ Estate are trying to create the same kind of link between MJ and Halloween that Mariah has with that album and Christmas.
Just to point out I DO like the album and bought my copy straight away. I DO like the cartoon. I haven't seen Thriller 3D but I DO like the idea of it, and I DO like the idea of trying to build on the existing, strong link between Halloween and MJ, it's just the strategy that I question.