Learn Dutch: Wat dat platform betreft, verdwijnt de reclame zodra je inlogt. - Regarding that platform, the advertisements disappear as soon as you log in.

It translates to "as for" or "regarding." In Dutch, it wraps around the noun or pronoun you are bringing up as the topic—in this case, dat platform.

Why does the main clause say verdwijnt de reclame instead of de reclame verdwijnt?

This is due to the V2 (verb-second) rule. The entire introductory phrase Wat dat platform betreft takes up the first position in the sentence. Therefore, the conjugated verb (verdwijnt) must immediately follow it in the second position, before the subject (de reclame).

What is the literal meaning of betreft in this construction?

Betreft is the conjugated form of the verb betreffen (to concern / to apply to). Literally, Wat dat platform betreft means "What concerns that platform."

Why is inloggen written as one word at the very end (inlogt)?

Zodra (as soon as) is a subordinating conjunction, which forces the conjugated verb to the end of its clause. Inloggen is a separable verb, but when a separable verb is pushed to the end of a subordinate clause like this, its prefix (in-) and the verb (-logt) are stitched back together into a single word.