Hi bong2x,
Sometimes obfuscation is used for protection and is not malicious by nature perse. But as one finds big chunks of obfuscation in a particular manner it is good to suspect it of something else. Both ad launchers and malcreants try to hide their code from the observant, the browser knows exactly what to run. Blocking is the safest way to go, ABP, NoScript, RequestPolicy extensions in the Firefox or flock browser and it does not trouble you anymore,
polonus