Hi, i am a new member too.
I am sure we both can help each other, so do not hesitate whenever you need some help.
Regarding your question about translation memories, iI do not have a clear idea, but in general I can tell you the following: they are programs which help you to translate, you insert an original text and its corresponding translation. Then, when you need another translation with the same characteristics (subject, field) you entry that new text. The memory is going to recognize the exact phrases that both the previous translation and the new text have. Those the memory do not recognize, you need to translate them, then you introduce the new translation to the memory to increase the capacity of the translation memory, and so on. Trados and Wordfast are just the most known, but there are others.
Sorry if I have not been clear enough, but it is all I know, maybe someone else can give you clearer and more information
Best regards