Chat me online wap

It is rather keeping each online user aware of the online-idle-offline states of their friends, so that conversations can begin.The naive implementation of sending a notification to all friends whenever a user comes online or goes offline has a worst case cost of O(average friendlist size * peak users * churn rate) messages/second, where churn rate is the frequency with which users come online and go offline, in events/second.This is wildly inefficient to the point of being untenable, given that the average number of friends per user is measured in the hundreds, and the number of concurrent users during peak site usage is on the order of several millions.Surfacing connected users' idleness greatly enhances the chat user experience but further compounds the problem of keeping presence information up-to-date.Now it's trying to find a place in the saturated messaging market with competitors that are offering the same features with a larger audience.

The project I'm currently working on, Facebook Chat, offered a nice set of software engineering challenges: The most resource-intensive operation performed in a chat system is not sending messages.While this architecture works pretty well in general, it isn't as successful in a chat application due to the high volume of long-lived requests, the non-relational nature of the data involved, and the statefulness of each request.For Facebook Chat, we rolled our own subsystem for logging chat messages (in C ) as well as an epoll-driven web server (in Erlang) that holds online users' conversations in-memory and serves the long-polled HTTP requests.Since its change, imo is another chat app looking for an audience.

Its usefulness was removed in 2014 when it stopped supporting third-party chat.

Knowing that your chats and video calls are encrypted is nice, but it's a feature you can find in other apps like Telegram or Google Hangouts.