Skype this week launched the GroupMe app for Windows Phone, following its August acquisition of the tool that enables free, real-time group texting. GroupMe lets you communicate instantly with up to 25 colleagues using chat, photos and location sharing.

Emails get lost and voice mails can take forever for someone to reply to. But with GroupMe, you can send a mobile message to an entire project team or department. It can help you keep your email inboxes clear if you just need to fire off a short message, like a meeting reminder. And the Questions feature lets you send a question to all members of your group simultaneously.

GroupMe is now unique, as one of its main rivals, Beluga, shut down last December. Google+ Hangouts allow you to video chat with up to nine contacts at once, but you have to actively be online to catch them. GroupMe, on the other hand, lets you send messages that group members can pick up whenever they log on.

Groups are capped at 25 members, and there is currently no option to leave a specific conversation within a group. If you leave the group, you cannot be added back to it again.

GroupMe is now available for Windows Phone, Android, BlackBerry and iPhone. Windows Phone users can pin their GroupMe groups of contacts to their smartphone's home screen.