The yeti is a USB-microphone by Blue (see official site).
It ranks #8 on Marco Arments Podcasting Microphones Mega-Review, here’s what Marco has to say:
… it’s a great value, and under ideal circumstances — close-up use in a silent, soft room with a pop filter — it can yield excellent sound quality.
The thing to look out for is that it picks up a lot of room echo. Buy a pop filter and get super close to it to get the best results (buy a boom arm or just stack a few books).
If you want to start a Podcast with multiple hosts but don’t want to buy each person a microphone, deal with audio interfaces or multi-track-recording, the yeti might be a good choice.
Use the bi-directional mode (looks like an 8) for a two-host podcast and the omnidirectional mode (looks like an o) for more than that.
Remember that with one mic you only get one track, so if you have more than one host, make sure everyone speaks at a similar volume and is at a similar distance to it. Auphonic can help as well and is generally recommended.
For everything else, check out How to start a podcast.