One of the less glamorous activities of a product manager is tracking what competitors do. Unless you're practicing a copy-cat business model your competition can't really teach you much that you wouldn't already know and tracking activity of competition therefore feels more like looking in the rear mirror. While looking what's happening behind your back is an important security precaution, most action happens in front of you and looking back feels boring most of the time.
If you're lucky you have half a dozen competitors (that is, just enough to validate your target market but not so many it would feel crowded) who release new products, make new deals, update their webpages, and do many other activities that you as a product manager must be aware of. Consequently keeping tabs on all their activities consume lots of time. At least for tracking updates to webpages there exists a nifty little service called VisualPing which tracks changes to specified web pages and notifies you by email or Slack about changes. After testing this service for a week I found out that it works quite well and, even more importantly, that also our competition is as glacial about changes to their webpages as we are with ours.