I have a few questions regarding light clients (such as Electrum and Multibit).
Are they connecting to full nodes directly (using port 8333) or to another kind of server on another port?
If they do not connect to the bitcoin network directly (on port 8333), why is that? Why is it necessary to be a full node (with the whole blockchain) to communicate in the bitcoin network?
In the case of Electrum, it seems to connect to an Electrum server, which runs a full node. What are the advantages of doing so instead of connecting directly to the bitcoin network on port 8333 (assuming that it would be possible)?