Are there any disadvantages of learning English by Skype?
There are a great many ways to learn English. Learning English online by Skype is one of them. It may seem the best option when we take into consideration the efficient use of time and the availability of the Internet worldwide. However, there are also certain downsides you should be aware of. So, what are the advantages and disadvantages of learning English by Skype?

Skype is a software application and Internet protocol that allows people to communicate by voice, video and instant messaging over the Internet.

The Pros

• Time efficiency. You don't have to spend time getting to the place where face-to-face lessons take place, nor do you have to spend time returning home. Skype lessons can be held in any place where a computer and stable Internet connection are available (usually, it's your home).
• You don't have to have a break in lessons when you're on a business trip or otherwise away.
• Study materials such as texts, tables, audio, video, presentations, etc can be transferred instantly. Therefore, it is often unnecessary to buy expensive books. Moreover, since you have access to the Internet, you can open study-related websites, listen to audio, and watch relevant video. This flexibility is not always easy to arrange with face-to-face lessons.
• You can have lessons with a teacher from any part of the world, including native speakers from an English speaking country (when you schedule your lessons, make sure you take time zones into account).
• You don't have to spend money on public transport and/or petrol.
• Extremely flexible schedule. You can re-schedule your lessons by mutual agreement with minimum "harm" done.
• Some professional teachers record their lessons and send them as an mp3 file to the student who can listen again and again to the lesson.

The Cons

• Difficulties in doing certain types of exercises that may require additional expensive software.
• Possible technical problems with the Internet connection, microphone, webcam, computer, etc.
• Some people find face-to-face lessons much more convenient and nicer. Although this is not very common, they may feel uncomfortable communicating by means of technical devices instead of talking face-to-face. They may not even realize this, but it will surely have an impact on the effectiveness of the study process.
• Skype is not the best learning tool for children younger than their teens.
• When lessons are held without a webcam, it is impossible to see the actions of the person you talk to. Some people, especially novice learners, find it much easier to understand speech when they can see the face of their interlocutor.
• If a person already spends a lot of time on the computer at work, additional time spent at the screen may have a negative impact on his or her health.

The Myths

• Skype lessons are cheaper than face-to-face lessons. This is often, however not always, true. If you want to have a professional teacher and schedule your lessons at the time most convenient to you, the cost will often be as high as for face-to-face lessons. Individual lessons also add to the cost.
• Online teachers provide qualitative lessons. Unfortunately, this is not always the case. There are a lot of bunglers as well as those who simply hold theme-based conversations with their students instead of qualitative lessons. If your main aim is to have theme-based conversations in English, then Skype is a great way to implement this idea.
• A lot of people think a webcamera is always used in Skype lessons. This is far from being the truth. Many teachers prefer to hold lessons without a webcam because they consider it to be a distracting rather than a helpful factor.
• Skype lessons are always held with one student (yourself) at a time. This is not always so, because Skype has group call functionality that allows communication with a group of people at the same time. Some teachers use this functionality.
Read this article in Russian.

Read also: Teaching English by Skype - Interview With Bea Koch

 " Difficulties with doing certain types of exercises that may require additional expensive software."
This may be true. I don't know exactly what that could be but I think it is about softwares that now only big and very well organized online ...
  For me, Skype is nice to chat with people from abroad - what improves my English as well. But to talk with a teacher? Well, I never tried yet. But somehow I can't imagine that it works fine for me. Once I took French lessons in the evening and I ...
  Online lessons, a virtual class are like in real life just that you don't see the others, but they are there and you communicate with them in real time, with real people, real students, just like you and with a real teacher. They are very well ...
  Best idea to connect with people who are going to teach us!!!!!!
 I have used Skype recently. My Skype : [Any and all contact information or personal links should be placed in your member profile.]. I would like to chat with people in the world. Thankyou !
 "Difficulties in doing certain types of exercises that may require additional expensive software."
As someone who has been teaching on Skype for several years, I cannot even begin to imagine to what you are referring. We live in the era of Web 2.0 ...
 i really would like to talk with friends in the world,my skype : [Any and all contact information or personal links should be placed in your member profile.]
 my skype is (Removed- Please put contact information only in the Contact Information section of your profile) please join me and we will talk in english thanks
  Can I join too ?
  Like everything in life there will be pros and cons. In my opinion, skype opens more pros than cons in language learning and some of the cons listed above apply to face to face lessons too.