my take on it

Twin Flames have no karma to work out between them, there never has been, never will be and come together for no other reason than unconditional love. Twin Flames love each other with no expectation of the other and with no conditions attached to the giving of that love. It is easy to say that you love someone unconditionally but you need to ask yourself could you love this person if for some reason they could not remain with you? Could you give your love to this person with no expectations, not even that the love will be returned or even recognized? Can you love this person for no other reason than there is simply no other option available to you? If you can answer a resounding (and honest) yes to all of the above then you are experiencing unconditional love. But be careful here my friend for Spirit is listening and may put that love to the test, Spirit may require that you prove yourself worthy of this love and place you in a situation wherein you must truly discover if this is an unconditional love by separating you, sometimes only temporarily sometimes permanently, depending on what lessons you have to learn in this lifetime.
Which brings us to another point, Twin Flames are earned not a given, you must prepare yourself to be able to join with your twin flame, it is not an automatic, it is a gift. And as a gift, it is truly a privilege to know your Twin Flame but you must be ready. How do you become ready you ask? Well you will have to learn to love deeper than you ever thought possible and that usually means meeting, loving and losing "near twins" which are in reality Companion Soul Mates. Are you brave and strong enough to be able to risk loving with your heart and soul just to have the dream shattered? If not then seeking your Twin Flame is not for you for you must deepen your capacity to love before you can know unconditional love and that means experiencing pain as well as joy. The more pain you have experienced the more joy you are capable of holding within. Sometimes the cup of love must be completely shattered before it can be built strong enough to hold the love of your Twin Flame. Steel is tempered through flame and your heart must be tempered through pain before it is strong enough to protect the love of your Twin.
When Twin Flames come together they become one, they are not like each other, they are the mirror image of the other. They think alike, they hold the same values and often their life experiences are very similar, sometimes they will actually look like each other. By that they will have similar builds, bone structures and features. This is not however a guide as to whether you have met your Twin Flame or not.
Twin Flames do not teach each other, they learn together and help each other learn the lessons that have been set before them in this lifetime. When Twin Flames come together they join forces and are capable of overcoming obstacles the average mortal could not begin to face. They are so filled with unconditional love they literally glow with it and have much to share with others. They are the inspiration that poets write about and singers sing about.
Another warning I would give at this point is that it is important that we avoid the trap of measuring each relationship against what we believe a Twin Flame to be. For by doing this we lose the opportunity of experiencing all the love that is placed in front of us. Keep in mind that no matter what, if we are to be with our Twin Flame then it will happen and by experiencing the loves placed before us by Spirit we are preparing for the day that we meet this special, special person. We also need to keep in mind that we are not destined to meet our Twin Flame in each and every lifetime. The chances of meeting this one perfect mirror is very slim, it does happen and it seems to be happening more now than ever before, but there are no guarantees.
Personally I feel it is more important to be aware of the different types of Soul Mates than it is to seek this one perfect relationship, or to label each relationship we have. Simply knowing this information is more often enough for it helps us understand why we feel such strong connections to people. This is the reason that I have stopped leading the Discussion Groups in SpiritWeb Chat on Sundays on this topic, I felt that there were people that were putting on the blinders to other relationships and searching only for the Twin Flame, please don't do that. This is not the intention behind this sharing of information.