Fascinating article by Rabbi Yair Hoffman dissecting whether or not using the Amazon Echo’s voice-activated features violates the Jewish prohibition on working on the Sabbath:
Like most technology, Amazon Echo carries with it a number of fascinating halachic questions. What are the prohibitions associated with its use on Shabbos? If one avoids using the name “Alexa” in conversation, may one leave it plugged in on Shabbos? Is there any circumstance in which it may be used?
The link in which I saw this asked whether the Echo might be the new Shabbos goy, which is to say a non-Jew who essentially carries out work for observant Jews on the Sabbath. Rabbi Hoffman concludes not, but that’s not to say there might be alternative interpretations.