Basically, if Facebook is really building up profiles of people, then the EU standpoint is clear across the board that you don't even need to be able to actually name the person from the data in order to be governed by the data protection laws, and e.g. details like IP addresses that are not considered personally identifiable by themselves easily becomes so when combined with other data.

It is very unlikely that they are compliant anywhere in the EEA if they're not compliant in Belgium.

Their argument that they're only subject to privacy laws in Ireland is a total non-starter, as it "worst case" for Belgian authorities just means they'll have to go after Facebook in Ireland, and given that all EEA countries have privacy legislation closely modelled after the Data Protection Directive, it's highly unlikely they'll get a better result there (and if they do, it'll get appealed, and if they win an appeal, the law is likely to get changed.

If they are maintaining shadow profiles, then what they do is very, very obviously at odds with the principles the Directive are based on). More likely I'd expect Belgian courts to insist they have jurisdiction on behalf of victims in Belgium.

In either case, as soon as this case is concluded, you can expect a bunch of other EEA states to pile on.