Do you have questions to pause? Or just looking for the reviews of previous travelers? I am going to propose to you here 3 forums, starting from the worst towards the best, a personal opinion which concerns only the destination Madagascar, the participants being different according to the places of residence.
I do not advise you on destination Madagascar. The Routard has been a must for many years but today, if you read the Routard, you will never come to Madagascar!
You will tell me "but the participants are residents". Yes, but take a step back on what some residents say. As much as you can find Ali Baba's cave of information, discussions, wonders, as much on the embittered service ... Living in Madagascar is not always easy and
a lot some become embittered, say things they do not really think but fatigue and alcohol makes talking easily. Others behave very badly (slavery, young ladies and others), are expelled where leave of themselves even after having them worries (those have looked for it) and come to complain on the forums, which is the case on the backpacker, so take with tweezers the writers of positions on the Backpacker (the 48-year-old single life in Paris and the poor, the 18-year-old did not really like him and he suffers from having been cheated, sniff).
A good forum, former vacationers participate as residents. A good atmosphere and relevant information, even if some disturb sometimes made, the moderators are present and do a good job (I specify, the goal of the moderator is not to transfer what not to say on a destination but the way to say it, without insult for exampleDiscover
A forum not quite as the others you guessed, it is mainly expatriates who participate. However if you get a realistic opinion about Madagascar, Resident's reviews talking to each other and not newspapers, you'll be thrilled! And do not hesitate to participate, they are not meanDiscover