A browser to mark, track, notify about text changes on web sites (prices, rates)
You can tap (and hold) certain elements on web pages - such as prices, exchange rates, amount of comments or followers, "out of stock" labels - then save them as a target for the app to track their changes over time by checking the page once in a while, automatically. If the text has changed according to your preferences (like a price drop or exchange rate hike) then the app post notification. There are also phone desktop widgets available.