It makes sense to track your stock portfolio's performance online: quotes are updated in near real-time, your securities are linked to information and analysis for each stock... All you have to do is enter your transactions at home and you can then check your portfolio in the dodgiest-looking internet café in Lagos without worrying about the sysadmin investing all the cash at your actual broker in ZZZBest.
This blog reports on the major websites that allow you to track the performance of a portfolio of stocks online, for free: Yahoo! Finance, Google Finance and AOL Money & Finance, etc.
Hopefully, it will help you find the best free online financial portfolio service for your needs!