Watchlists are lists of stocks that you want to keep track of, and allow you to quickly view the data for your saved set of stocks. They are similar to portfolios, but simpler, as they do not contain quantities, cash, or buy prices.
Stock Rover allows you to create multiple watchlists so you can group stocks by type, such as value, dividend or momentum stocks. As with a portfolio, you can chart a watchlist to compare against stocks, indices, industries, portfolios, or other watchlists. When watchlists are charted, an equal allocation of capital is assumed for each stock.
There is a video that shows an overview of watchlists. The video can be viewed here. Please note that this video was recorded on a slightly earlier version of Stock Rover, so there may be some minor differences between the product you experience and this video.