Following Company Web Sites and News
Create a bookmark group of company web sites in the same way you can create bookmark groups for web sites of any kind— no difference.
Company web sites for stocks I follow are most usefully bookmarked at the news page for each company. That way I can use the cmd-w keyboard shortcut to quickly scan through numerous web sites for news.
Most companies have an RSS feed icon that show on the web site, which allows seeing news releases pop up right in your mail program or other RSS feed reader. Click on the icon and something appropriate will happen. I actually like this approach less than viewing the company web sites, but in theory it is more efficient— try it and see what you prefer.