It seems like a real offer from YoBit, but that doesn't mean you should take it.
I'm not involved with YoBit. I am involved in investing and these types of offers are easy to assess based solely on how much interest they're "promising" to pay you and comparing that to what's available in the marketplace.
For an offer like this to profitable for YoBit they need to be able to make more interest on your money than they are going to pay you for the time period.
Here's a list of annual interest rates by country:
https://www.deposits.org/savings-accounts.html. The highest rate is 20% per year. So if YoBit is going to offer 3% per month on BTC they need to be able to make more than 3% per month with the money you've invested to make a profit...which is the only legitimate reason someone would make this offer to you.
We don't know what YoBit is doing with your money, but a good estimate is to look at what interest rates are around the globe. The most conservative thing they can do is reinvest your money at a higher rate. So if 20% is the highest rate globally that's available, how are they going to pay you 36% (3% per month for 12 months) without taking on some serious risk? And where there is risk there is the opportunity for them to lose your money.
They're probably investing your money in mining, which may give them a decent return and enough to pay that 3% reliably, but it's still a risk offer for YOU!
Be careful with this shit.
The next thing to be wary of is a lock-in period for your investment. If they require you to keep your money with them for a minimum number of days, weeks, months, run away as fast as possible. They can vanish at any point during that lock-in period and there's nothing you can do but bitch to us on this forum about how YoBit hasn't been responding to your emails, asking us if we think it was a ponzi scheme.
Good luck to you.