VisitURL is not a fully-fledged bookmark manager. It is not a replacement for Netscape's bookmark file or Internet Explorer's Favorites. It does not organize bookmarks into categories.
VisitURL is designed to help maintain a handy (as in: at hand) list of URLs that you intend to visit. For instance, if a friend sends you an email recommending that a particular URL, Visit is a good place to store the URL until you are ready to launch your browser and go surfing. If you copy the URL to clipboard, Visit will automatically intercept it and save to its database. If you copy several URLs at once, Visit will get all of them. (You may also add URLs manually or directly from an open browser window.) If you copy the URL with some text around it, Visit will optionally treat that text as a description for the URL you copied.
To access the bookmarked site, you can either view the HTML page that Visit creates in your browser, or click a toolbar button to launch the browser directly from Visit. There is no limit to how many URLs you may store, though the program is primarily designed to hold, view and edit a short, temporary list. Netscape and Explorer tend to consume so much system resources that it's not practical to keep them loaded at all times - this is where Visit comes in.