Giustino is wondering why Russia is in the G8 while Brazil isn't. To answer both him and my president, the reason why Russia is tolerated in the G8, and Brazil hasn't been invited, is because G8 membership is important to Russia, but irrelevant to pretty much everyone else.
G8 membership was Yeltzin's great public achievement. In the early 90s, G7 countries were the ones most intimately involved with introducing free market values this side of the Iron Curtain. Therefore G7 meetings were always on the news, the decisions made there always seemed pertinent; it was easy to believe that G7 was the club that mattered, the table from which the world was run. Joining the club was a boon for Russia's collective self-esteem, as it was now accepted as an equal to the US, UK, France, Germany... In Yeltzin's time, Russia did have industry - it was outdated, inefficient and crumbling, but it was there. And for all the corruption, violence and nepotism of the time, Yeltzin's Russia was - when it counted - democratic. In Yeltzin's Russia, professional clowns like Zhirinovski or the communist Shandybin could rise to political prominence; a stand-up comedian with a rustic, country farmer public image rode his fame to a governorship; and like so many great authoritarian leaders, Putin himself was elected legitimately*. To the G7, Yeltzin's Russia was a misguided, but promising partner, a project that they felt confident they could manage**. Letting Russia into an organization of large industrial democracies was not a big deal for the others, but it was a massive plus for Yeltzin and his nation.
Today, we live in a different time. The West's biggest issue is no longer incorporating Europe's lost half into an industrial democratic community. That job is by and large done. Most of Eastern Europe is either in the EU or well on its way there. The Balkans appear to have been sorted. Ukraine may still see scuffles between the revolutionary president and other major figures, but overall it has been realigned westwards. Belarus is irrelevant. Transdniester will eventually be sorted out by Moldova, which is to Romania as Estonia is to Finland. Chances are that if Georgia gets an EU invite on the condition that it drops Abhasia, that issue can be solved.
For the Golden Billion, both the major issues and the major weapons are now economic. Noblesse oblige has been re-targeted to emerging markets. Wars have outlived their usefulness; I won't claim that we've seen the last truly massive war, but at this point in time, there is no viable hostile force to challenge the West's domination. The issue is the availability of energy and access to markets.
And Russia aside, the Grand Number does not have a cohesive position in this effort. The EU's previous and early iterations were about establishing a common market; Europe as any sort of cohesive political force has only been around since the Iraq war, when the continent's big players either said no thanks, or made it very clear that they were only sending in a token mercenary force as a personal favor to Washington. If the G7 does not have a common approach to the Middle East, the organization itself does not hold any special significance. It's not really useless, as it's still a good excuse for world leaders to get together and talk about things, but the G8 is a far less important event than the World Economic Forum, let's say.
The reason why Brazil, or indeed China, have not been accepted into the G#, is because they haven't asked. They have nothing to gain from it except the ire of anti-globalist protesters. In terms of international politics, Brazil is naturally poised to assume the same sort of leading position for the non-Arabic Third World as Poland has for New Europe, and G8 membership would only hurt that, without providing any sort of real prestige.
The reason why Russia has not been kicked out of the G8, despite being increasingly totalitarian, is because nobody particularly gives a damn if it's there. Russia enjoys its G8 membership a lot more than the G7 minds it. Europe's attitude to Russian antics is the one Estonia should've taken up in a perfect world: that of confident bemusement. As I've written before, Russia needs Europe a lot more than Europe needs Russia; but that doesn't mean Europe is going to go around hitting the Kremlin in its collective face with a wet trout. While Estonia has the habit of calling Russia's bluff and allowing it to make a fool of itself, Europe simply ignores the pointless dick-waving and humors Putin in irrelevant cases.
* Russia's problem isn't that Putin crushes all viable competitors, it's that there are no viable competitors to consider. The tragedy is that Putin is actually the archetypal Russian leader; history tells us that the country functions under totalitarian rule and falls apart under democratic idealists.
** Remember, Putin came out of nowhere. In hindsight we know that he was involved in St. Petersburg mayoral politics, but shortly after Yeltzin's resignation there was a memorable moment at an international conference where some Western journalist asked, "But who exactly is Mr. Putin?". So the G7 actually had every reason to expect Russia to continue on a democratic path.