It's from @steembasicincome, which for all I know could end up being some weird pyramid scheme, but if it was they're really doing it wrong, because they seem to be working as intended instead for now.
Basically you send 1 steem to them with someone else's username in the memo (with or without the @ before it), and then you and they are enrolled. Enrolling in the program gets you a share in one of their voting pools, you can have more than 1 share, some people have hundreds.
You get bonuses to the vote they give you if you vote on their post updates, up to 100% bonus.
Your shares entitle you to a certain amount of their voting power every week, you need to make at least 1 post a week to get that voting power for the week, if you post more on average they reduce the vp to balance it out to be the same in the long run.
They buy delegations with the steem which is why you can't buy them with sbd.
I've been giving people SBI shares because I lack a sufficient high-powered voting base on my posts and want my account to be self-sustaining at a high level of giving, and to give others a little something extra on their posts past the amount my voting power alone would be able to afford. I will feel very bad if the steem price totally craters and the votes are worth near-zero, at which point I'd have to buy more steem and buy more shares to get them all over the 0.02 level, if the program still exists.
Also, if the total amount of SP your followers has exceeds a certain amount, it's worth it to post from busy.org, because their bot will vote on your posts (for a few cents up to a few dozen cents, depending on your following and random other factors I don't know)
LOL I kind of want to use that as our promo quote.
Bahahaha
Ah I see, so it costs 1 SBD per share? I went ahead and got you one share to test it out, also sent a few other users from this post a share too.
Oops, sorry it's 1 steem a share, don't worry they'll refund you those sbd, though they do a lot of things manually so it might be a while, including the sign-up process when you send them steem.