Performance of the company

Publicly traded companies issue annual reports that can be requested from the company, or often be found at local libraries. You can trace the performance of stock on the appropriate exchange. If it is an internet company it is far trickier. Most internet "businesses" do not follow the normal rules of business reporting. Many simply lie about how long they have been around and their actual perfromance. There is no auditing procedure to check them out.

Besides finding out by personal experience, I would ask around. Also you could call your local better business bureau.