The network and website itself is dead, admin is sleeping and running his own ponzi/scam referral links on the network. One of my friend gave application to accept website after weeks no reply yet
sorry but this is just FUD
i'm a publisher with mellow ads and it is currently (although not always) the best paying btc ad network. of course you need good Alexa ranking before they will even consider you as a publisher.
ive also ran ad campaigns there without any issues - pretty decent results. its best to wait until the network pool is lower to run campaigns then you get a bigger % of the pool and more traffic!
and the 2 times ive contacted them with queries i got help within 24 hours. i reckon they just ignore anyone they think is dodgy/scammer as it takes too much time!
other than mellow i would only recommend coinad and cointraffic if they will accept you - all the other networks are either trash payouts or reject you (and dont pay) for stupid reasons