Can one answer amein to a brocha heard on Skype?
Perhaps it is better than the shul in Alexandria?
Will a Skype connection help for joining together for a davar shebekedushah?
Rav Shlomo Zalman (Minchas Shlomo 1:9) explains that the reason why amen is not answered for a berachah over the phone is that there is no geographical connection between the parties. Although Skype allows one party to see the other by a camera connection, this does not form a geographical connection between them, and therefore the halachah will not change.
[See the previous answer on this topic at https://dinonline.org/2011/09/18/berachah-over-the-phone/.]
Seeing one another does form a connection between the two for purposes of davar shebekedushah, but this will not be effective when one sees somebody else over a Skype connection (for example, for purposes of a mezuman). The connection has to be a “physical” connection, which seeing is an indication of. A video/Skype connection will not be valid for this purpose, because it does not imply any “actual” physical connection, and people separated by continents can be ‘joined’ by Skype.