Well I happen to be one of the people who restart Yappari every now and then, and I'll explain why. It doesn't cope that well with dropped connections or changing connection from WiFi to 3G. I know the last one is a known bug. Anyway, sometimes when I'm on a train, connected to alternately 3g and 2g and sometimes without reception at all then it sometimes assumes I'm still logged in, but I can't send messages. Only a grey V mark. Even if the reception restores after that. In some cases I try to send contacts in order for it to connect again, or I try to restart Yappari. Either way, the messages with the gray mark won't get send and I have to type them again.

I've had this problem for quite some time, but I guess I can live with it. I probably won't be able to send a log anytime soon because this usually occurs in a train or car and I won't travel much in the coming days.