Communication in Eve is essential and is the lifeblood in any group activity. Most of the time it can make or break a situation, it can be a simple mistake leading to the destruction of billions of ISK or it could be as simple as mentioning that there is a fleet of 30+ cruisers roaming about. In Eve there are many ways to communicate but the most often referred to is being on comms. While typing, and broadcasts work in some situations that ability to communicate verbally can be much more informative and quicker. Being able to talk with people is so important that Eve even includes their own voip type service.
I was considering how I play now and from when I first started and I remembered an experience I had with an Eve player I had just met. We got along ok and ran missions together every now and then. After a little bit of time, I had finally worked my way into battleships and bought myself an Abaddon. I had large lasers to 1 and Amarr battleships to 1 and thought I could take on the world (npc world). Running my first level 4 mission was an eye opening experience at the difficulty jump from each tier of missions. Let's just say my first level 4 took me 3+ hours to do because I kept having to warp out and back in at range to make use of my beam lasers without taking too much damage. This led me to grouping up with the guy I had met earlier.
So we fleeted up and started Eve's voip service and accepted a couple of level 4s. We ran his and moved over a couple of systems to start running mine. The whole while chatting and communicating on which targets to focus etc. Warping into my level 4 mission we started shooting Guristas Pirates, since he had arrived before me all the NPCs had aggressed him first. Well we're in there for a minute when he tells me he needs to warp out. I agree, thinking he needed to warp out dock for some instant shields and capacitor and then warp back. So I continued to poke away at ships while my shields and then armor start to drop. This "friend" still hadn't warped back in to help finish the mission, and when he had warped out we were in no way close to finishing. As my armor begins to drop and my large armor repair is sucking my cap dry (along with the stupid large lasers) I align out and wait to hit warp until I just start into structure.
During this whole process the response I kept getting was that he was on his way. So I continue to steadily chew through the mission, the mission gets to a point where it is too much for my Abaddon to handle that I forcefully say over the comms demanding where he is, turns out he was 10 jumps over looking at modules to buy. This is where we encounter miscommunication, why he decided to go off while we were in the middle of the mission I have no idea; you can look at modules when we're finished.
This type of miscommunication continued on until I finally distanced myself from said acquaintance. While I never lost anything major over it, the constant repeat of this type of attitude became too frustrating to deal with. While communication sometimes just gets messed up and may happen repeatedly, it really gets tiresome after a few months without any improvement.
Whether you use chat or comms, make sure your intentions are clear. While in my situation I learned that you do not use the station repair services to fix your armor tanked Abaddon, you may end up getting your ship welped, or even the fleet you are in.