For desktop and mobile, I created my own (free) Slack workspace and then installed the RSS slack app (https://slack.com/apps/A0F81R7U7-rss) allowing one to subscribe to feeds and benefit from Slack's notifications. Works well for me.
Nice idea, but scrapping MarineTraffic.com data is against the terms, according to MarineTraffic.com. They provide a premium API for that. There are very few real-time AIS data sources that are freely available to the public unfortunately.