Blackberry Messenger (BBM) is a combination of services that can be used with groups of contacts. It allows you to send SMS/MMS-like messages to your contacts without requiring a data plan provided your phone is equipped with Wi-fi. The service is available only to Blackberry users. Blackberry users experienced outages this month and most users could not access the service for days.

If you are an avid user of the BBM service,there are a number of alternatives out there that function exactly like the BBM. Some of the applications can even function across all major platforms and offer complete functionality to your smartphone.

Whats App Messenger:   The application utilizes push notifications to instantly get messages from friends, colleagues and family. Switch from SMS to exchange messages, pictures, audio notes and video messages with WhatsApp users at no cost. WhatsApp Messenger is cross platform and available for iPhone, BlackBerry, Android and Nokia

GroupMe:  GroupMe is a group messaging and conference calling service that lets you stay in touch with groups of people via mobile phones. It’s a free service that allows users to create and manage groups that, in effect, create an SMS-based chatroom.

LiveProfile: It is an IM app for iPhone, Android and BlackBerry devices. It is totally free and looks quite similar to BBM.

Beluga lets you send and receive instant updates, location info and photos, all via push notification, with NO TXT messaging fees.

PingChat!Ping allows you to connect to friends using a Ping! ID, something akin to a BBM pin, but easier to remember because you can pick it yourself. Once you’ve shared your ID, or found friends via email, Facebook or Twitter, you can send text messages, photos, videos, voice memos, contacts and map locations. PingChat! is available on iOS, Android and BlackBerry, and is ad-supported.

Cnectd lets you chat across iPhone, BlackBerry, Android and Symbian devices. In addition Cnectd allows you to find new friends in your area, share media with your contacts and more. Cnectd alerts users of new messages instantaneously ensuring that you’re always Cnectd!

Kik Messenger is a real-time cross-platform instant messenger application for iOS and Android. And now available for your Blackberry. You see when messages are delivered and read and even when your friend is typing, giving your chats an undeniably instant, face-to-face feel.

ChatPlus is an iPhone and android chatting service which allows you to chat with your friends without having to pay for text, photo/video/voice, handwriting and location.