Depending on where I am, I do on few occasions get a random invite or a whisper to join someone's group. Most of them that have attempting to recruit me were the sort of random made groups or ones that have nothing to say in the group bio (I like to see what the group is about, I like story). Some are pretty odd or simply just not in the credit of being a role-play group, like all Out-Of-Character conversation and no role-play. I get invites either after I've role-played with someone or just out of being a certain species like a hyena or cheetah.
Also, in the rare moments of my play, I decide to accept a group invite just for the sake of giving a group a chance. I don't like to feel as if I haven't, for the very least, gave a random group a try. A few of them were actually pretty ok, the players were interacting with one another, the leader was fun, and I stayed on for a good bit before I had to log off. I think the best random group I joined was this pack, this was a long while ago, so, I cannot remember the name of it. I was a scout for the group. I thought it was really fun, the leader of that group created their own conflict with the wolves and a plague being contracted by large insects. The session was really fun and I liked it. The whole fight with the bugs, I thought, I was cool and it had me guessing who would come out alive, including myself. The pack disbanded a few weeks later, but for the most part, I did like it anyway and was happy to be apart of it.
Another group I was invited to at random was pretty much a one-day group, but I had a bit of fun in that one. It didn't have a whole lot to it, but it was still alright for me to stay online and play with the members. They were friendly with one another, each member had a task to do, and the leader of it was nice. Like I said, not alot, but still something to have a good playtime with.
So yeah, not all random invites lead to a boring or derpy group, but just in my opinion, giving that occasional chance with one and see what you think.
