When Skype came out in 2003, it seemed to be more an improvement of the Messenger services more than anything. But with the roll-out of smartphones, Skype elevated to a potential communication app that allows voice over IP services for free.

And for a while, the pool of users expanded, until some started to wonder if there are other services that offer better features or just another platform where you can connect with friends.

Viber

Its most recent milestone is the 175 million users currently using the feature. But, according to TechCrunch, the bigger news there is that the number grew from around 140 million just two months ago in December.

Since its release in 2011, Viber has continually offered top-notch services for free, including all-the-time connection (provided that your contacts' phones are turned on), instant message reply via a pop-up screen (so you won't have to open the app each time there's a message), voice chats, and group chats, all without draining your battery, reports Stuff Magazine.

Oovoo

Users of iOS, OSX, Android, and Windows now have something to rejoice when it comes to video chat apps for free, with Oovoo.

According to PC Mag, Oovoo has a wide array of features including group video (up to 12 friends at once), voice calls, and video calls on one's desktop and mobile, for a fuller, all-around video chat experience.

It doesn't stop there. On its official website, Oovoo allows for screen sharing, send files, video call recordings, and instant messaging of up to 12 friends.

Voxox

If you're looking for the most comprehensive app that offers what may be the widest array of tools and services, Voxox can be the answer to your needs.

Its list of features surpasses the likes of Trillian, Skype, and Google, to name a few, as it offers these features and more: Facebook Chat, massive share filing via email, IM or SMS, calls via video, conference, and desktop, world-wide two-way SMS, Twitter updates, Skype IM, call screening, and emails.

This doesn't mean that you can get your hands on all of these for free. According to Laptop Magazine, there are corresponding rates that can apply with Voxox. For instance, as an initial user, you get two hours of free talk, after which you would have to purchase Vox points, amounting to roughly a minute of a call for each point.

But it does have an edge over Skype, as you get no extra costs for receiving incoming calls and even forward calls to your mobile or landline phone with your own Vox PA.

If you do decide to go for Voxox, you may have to deal with the heavy installation size of 25mb, which can not only be a lug for those who want to save on space but also a lag in terms of downloading.

WhatsApp Messenger

The supposed contender to BlackBerry's messenger service, WhatsApp seems to have the edge with its availability for Android, BlackBerry, iPhone, Windows Phone, and Nokia phones.

All you need is a Wi-Fi connection or 3G and you can always stay connected to your contacts. Its features include sending video, images, and voice messages, group chats with friends, free international messages to anywhere in the world, offline message retrieval, and location sharing.

Just like Viber, WhatsApp uses your address book as your own contacts, so anyone of your friends who are already on WhatsApp will automatically be displayed.

The good news here is that your first year of service is free. Afterwards, you only need to pay $0.99 every year after.