Again - depends on how geeky you want to be. You can also assign a single person to do everything - organize and/or purchase/supply all the wines and arrange for bread and cheese. It's why it's a good idea to have a budget to which everyone has contributed at the beginning of the year, rather than rely on month to month volunteers. A couple groups I'm in have been going on for many years - everyone just knows what day and time and it's always at the same place, so there aren't any emails at all most of the time.
That relies on people having developed a bit of comfort w each other over the years and also similar commitment. Personally, I think it's best to pour all the wines at once so you can compare every one to every one and you should of course rate every one too, not just your favorites.
On the other hand, you can just have people show up with something they love and serve it non-blind. That's exactly what I did last night and it's an absolutely fine way to have wine with friends. It's the way you really want to drink most of your wine and unless you really want to be a bunch of geeks, it's probably a better way to get people together. Especially if people aren't in the business or professionals or super-dedicated amateurs, it's the way to go.