You're seriously trying to educate me on how politics in the US works? Perhaps you're unaware I'm both a US citizen and military member, was once a registered member of the Republican party, and have an understanding on political engineering and propaganda use by both sides. I'm fully aware of how political parties capitalize on public interests, issues, and emotions to capture votes and retain power. I'm also aware one party has massively influenced elections through gerrymandering, how both sides have sold out to corporate interests, how a certain news networks is the defacto voice of a particular party, how both parties use the military as a pawn, and how one party appears to have a bit more concern for its citizens as a whole versus just the rich elite and wall street. I'll let you figure out which is which.
Maher is fairly well known, especially those with access to HBO and/or a clue about media personalities. He can be extremely vile, right or wrong, on some subjects (Republicans, Tea Party, religion (especially Islam)) and calls out both sides (he has called out Democrats too, numerous times). He's also given free passes to such persons as Darrell Issa and Ann Coulter because they're his friends. Hannity and Limbaugh only speak rhetoric that fits the views from his respective bubble (a very small bubble); I've witnessed Maher spread his rhetoric all-around the political scale, and have disagreed with him on some issues (Marissa Alexander, his attacks on Islam as a whole, etc.). Hannity and Limbaugh have rarely called out a Republican, unless said "RINO" has suddenly done something that no longer fits his myopic view and now needs to be castrated by the supporting base. Example 1: Christie was the man of the hour for these two clowns until he dared embrace President Obama after a storm ravaged his state. Example 2: Boehner for not doing whatever.
There's a massive difference in how these individuals reach an audience. Hannity and Limbaugh capitalize on scaremongering a clueless, often older crowd, almost exclusively white, with outright lies, partial facts/truths, bigotry and homophobia, and warped opinions. Maher is very patronizing and goes on his rants as well, but he's not in the same class as Hannity and Limbaugh. I'd put Maher closer to O'Reilly who is also nowhere near the imbecile that is Hannity and Limbaugh. Maher and O'Reilly are smart individuals that can often hold an honest debate or conversation with others (as seen during Maher's panel discussions and O'Reilly on The Daily Show and debates with Jon Stewart). Hannity and Limbaugh are incapable of doing such, as fairness, honesty, and professionalism is not in within their capacity. Another I'd mention is Beck, the religious tin foil hat moron who uses outlandish assertions and scaremongering to capture his audience (he's basically Alex Jones with a bigger media presence via his time with FNC but less lunacy, which is saying something considering how odd Beck is). All of them are capitalists and happily accepting the dollars that fill their bank accounts. Hannity, Limbaugh, Beck, and Jones are obvious charlatans, with Beck and Jones likely possessing a mental illness of sorts.