The reason that we live in good times is that markets give people a selfish incentive to seek to perform actions that maximize total utility across all humans in the relevant economy: namely, they get paid for their efforts. Without this incentive, people would gravitate to choosing actions that maximized their own individual utility, finding local optima that are not globally optimal. Capitalism makes us all into efficient little utilitarians, which we all benefit enormously from.  

The problem with charity, and especially efficient charity, is that the incentives for people to contribute to it are all messed up, because we don't have something analogous to the financial system for charities to channel incentives for efficient production of utility back to the producer. One effect of giving away lots of your money and effort to seriously efficient charity is that you create the counterpoint public choice problem to the special interests problem in politics. You harm a concentrated interest (friends, potential partners, children) in order to reward a diffuse interest (helping each of billions of people by a tiny amount).

The concentrated interest then retaliates, because by standard public choice theory it has an incentive to do so, but the diffuse interest just ignores you. Concretely, your friends think that you're weird and potential partners may, in the interest of their own future children, refrain from involvement with you. People in general may perceive you as being of lower status, both because of your reduced ability to signal status via conspicuous consumption if you give a lot of money away, and because of the weirdness associated with the most efficient charities. 

Anyone involved in futurism, singularitarianism etc, has probably been on the sharp end of this public choice problem. Presumably, anyone in the west who donated a socially optimal amount of money to charity (i.e. almost everything) would also be on the sharp end (though I know of no cases of someone donating 99.5% of their disposable income to any charity, so we have no examples). This is the Altruist's Burden.

Evidence

Do people around you really punish you for being an altruist? This claim requires some justification.

First off, I have personal experience in this area. Not me, but someone vitally important in the existential risks movement has been put under pressure by ver partner to participate less in existential risk so that the relationship would benefit. Of course, I cannot give details, and please don't ask for them or try to make guesses. I personally have suffered, as have many, from low-level punishment from and worsening of relationships with my family, and social pressure from friends; being perceived as weird. I have also become more weird - spending one's time optimally for social status and personal growth is not at all like spending one's time in a way so as to reduce existential risks. Furthermore, thinking that the world is in grave danger but only you and a select group of people understand makes you feel like you are in a cult due to the huge cognitive dissonance it induces. 

In terms of peer-reviewed research, it has been shown that status correlates with happiness via relative income. It has also been shown that (in men) romantic priming increases spending on "conspicuous luxuries but not on basic necessities" and it also "did induce more helpfulness in contexts in which they could display heroism or dominance". In women "mating goals boosted public—but not private— helping". This means that neither gender would seem to be using their time optimally in contributing to a cause that is not widely seen as worthy, and that men especially may be letting themselves down by spending a significant fraction of income on charity of any kind, unless it somehow signaled heroism (and therefore bravery) and dominance. 

The usual reference on purchase of moral satisfaction and scope insensitivity is this article by Eliezer, though there are many articles on it.

The studies on status and romantic priming constitute evidence (only a small amount each) that the concentrated interest -- the people around you -- do punish you. In theoretical terms, it should be the default hypothesis: either your effort goes to the many or it goes to the few around you. If you give less to the concentrated interest that is the few around you, they will give less to you. 

The result that people purchase moral satisfaction rather than maximizing social welfare further confirms this model: in fact it explains what charity we do have as signalling, and drives a wedge between the kind and extent of charity that is beneficial to you personally, and the kind and extent that maximizes your contribution to social welfare. 

Can you do well by doing good? 

Mutifoliaterose claimed that you can. In particular, he claimed that by carefully investigating efficient charity, and then donating a large fraction of your wealth, you will do well personally, because you will feel better about yourself. The refutation is that many people have found a more efficient way to purchase moral satisfaction: don't spend your time and energy on investigating efficient charity, make only a small donation, and use your natural human ability to neglect the scope of your donation. 

Spending time and effort on efficient charity in order to feel good about yourself doesn't make you feel any more good than not spending time on it, but it does cost you more money. 

The correct reason to spend most of your meager and hard-earned cash on efficient charity is because you already want to do good. But that is not an extra reason. 

My disagreement with Multifoliaterose's post is more fundamental than these details, though. "It's not to the average person's individual advantage to maximize average utility" is the fundamental theorem of social science. It's like when someone brings you a perpetual motion machine design. You know it's wrong, though yes, it is important to point out the specific error. 

Edit: some people in the comments have said that if you just donate a small amount (say 5% of disposable income) to an efficient but non-futurist charity, you can do very well yourself, and help people. Yes you can do well whilst doing some good, but the point is that it is a trade-off. Yes, I agree that there are points on this trade-off that are better than either extrema for a given utility function.